Long before the biggest names in hip-hop and R&B had a chokehold on the Billboard charts, they were struggling artists looking for their big break. It used to be that aspiring MCs and singers had to sell their music out of the trunk of their cars, in hopes of getting a shot at stardom, but with the popularity of Twitter, Facebook and YouTube, the game has long since changed.

In light of a music year that has celebrated underground artists and catapulted them into the mainstream spotlight -- think Tyler, the Creator's Best New Artist win at the 2011 MTV Video Music Awards -- The BoomBox highlights an array of artists making big moves in their respective careers. While some mic holders on the list may be familiar, there's always someone who still needs to be put on to their magic. Then there's others whose buzz has the streets talking. Here's 15 up-and-comers making their mark in the the hip-hop and R&B game.

Elle Varner
Brian Killian, WireImage
Singer Elle Varner was pretty much destined to be a musician. The child of two songwriters, Varner developed an early love for singing and began playing instruments by the first grade. Varner has noted Stevie Wonder, Joni Mitchell and Chaka Khan as some of her musical influences, which can be heard in her soulfully edgy vocals. The MBK/J Records talent's latest single, 'Only Wanna Give It To You,' features Roc Nation signee J. Cole.

Luke James
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There are lots of male R&B singers in the game, but something about Luke James stands out from the crowd. The New Orleans native got his start behind the scenes, penning tracks for the likes of Chris Brown and Justin Bieber, but being in front of the spotlight is where he shines. James has a knack for conveying a soulfulness in his music and is a signee to super producer Danja's New Age Rock Star imprint.
Casey Veggies
He's only 18, but Casey Veggies is far from new to working hard in the music biz. The Los Angeles native went from top basketball prospect to aspiring hip-hop star, releasing his first mixtape, 'Customized Greatly Vol. 1,' at the age of 16. Since then, Veggies has dropped a handful of other projects, all while still attending high school. Since he recently graduated from his scholastic endeavors, he can focus on climbing the ladder of rap success.
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There's been a lot of good musicians to come out of Yonkers, N.Y. -- Mary J. Blige, Jadakiss and DMX -- and rapper-singer Outasight might just be the next big thing to hail from the city. Releasing six mixtapes as a free agent, it was only a matter of time before a major label came calling. Last year, Outsaight signed with Warner Bros. Records. His latest mixtape, 'Figure 8,' dropped in April.
Phil Ade
The hip-hop coming out of the tri-state DMV area -- Washington D.C., Marlyand and Virginia -- has been known to be eclectic yet unique at the same time, which is why Phil Ade joins this list. A self-proclaimed "everyday person rapping about everyday things," the Maryland MC signed to DMV crooner Raheem DeVaughn's 368 Music Group imprint, and has been generating a healthy amount of online buzz around the Twitterverse and beyond.
Jay Rock
West Coast MC Jay Rock is among the new school of Left Coast rappers making noise in the game. The 25-year-old pulls double duty as a solo artist and member of the rap group Black Hippy, alongside Kendrick Lamar, Schoolboy Q and Ab-Soul. In July, Jay dropped his long awaited debut, 'Follow Me Home,' featuring production credits from Cool & Dre, J.U.S.T.I.C.E. League and Terrace Martin.
Mac Miller
Roger Kisby, Getty Images
If Donald Trump compares you to the second coming of Eminem, you're kind of a big deal. Maybe The Donald only gave rapper Mac Miller the compliment for naming a song after him, but that still counts. Last year, the rhymer signed to Rostrum Records -- home to Wiz Khalifa -- and released his first mixtape, ,K.I.D.S.' Since then, he's received over a million views on YouTube for his 'Donald Trump' single, and appeared on the VH1 show 'Single Ladies.'
Childish Gambino
You may know Donald "Childish Gambino" Glover from his role as Troy Barnes on the NBC comedy 'Community,' but his rap alter-ego is much more interesting. During his time off from the show, the 27-year-old easily slips into MC mode, performing during the Rock the Bells tour this summer. Gambino got his name from a Wu-Tang Clan name generator -- yes, that's a real thing -- and has been touring the country under the moniker since signing with Glassnote Records.
Theophilus London
Theo Wargo, WireImage
Theophilus London is as polished as they come when it comes to his fashion sense, but his music is definitely out of the box. The Brooklyn native dropped his debut, 'Times Are Weird These Days,' in August, and is well on his way to changing the hip-hop game. Like a handful of MCs who are more interested in rocking a tailored suit than a gaudy diamond chain, London's music marries pop, punk and even R&B, all with a refreshing uniqueness.
Machine Gun Kelly
Johnny Nunez, WireImage
Machine Gun Kelly is a bad a-- and that's why we like him. As if his name wasn't proof enough, in late August, the Cleveland native rallied a fan flash mob via Twitter that ended with him being carried out of an Ohio mall by police. Earlier this year, the 21-year-old announced that he was signing to Sean "Diddy" Combs' Bad Boy Records imprint. Having already released a bunch of mixtapes, his major label debut, 'Lace Up,' should live up to the hype.
The Weeknd
Clinton Gilders, FilmMagic
The Weeknd is trying hard to remain so unknown that we don't really know much about him, but thankfully the music speaks for itself. The Canadian R&B singer released his nine-song mixtape, 'House of Balloons,' in March, and has had the industry buzzing about his sonic interpretation of the multi-facets of love. Tackling the likes of Drake's 'Trust Issues,' in promotion of his second mixtape, 'Thursday,' The Weekend showcases his originality even when he's covering someone else's music.
Meek Mill
Johnny Nunez, WireImage
You'd think working under a boss like Rick Ross would be daunting, but Philly native Meek Mill can hold his own. The 24-year-old started out under T.I.'s Grand Hustle label before legal troubles and a stint in jail prevented him from going through with the deal. Now an official member of the Maybach Music crew, Mill couldn't be in a better position. His gully style and lyrical wit set him apart from any would-be competition.
Tim Whitby, Getty Images
Say what you will about Natassia "Kreayshawn" Zolot, but she's got people talking. The Bay Area native raised on the streets of East Oakland, Calif. released the single 'Gucci Gucci' in May, and received over 2 million views of her video in two weeks. Although her music is more adolescent foolery than ghetto street tales, it was enough to make Columbia Records take notice, signing her to a reported seven-figure deal. If nothing else, it'll be interesting to see what the future holds for Kreayshawn.
Kendrick Lamar
Johnny Nunez, WireImage
When Dr. Dre gives you a co-sign, you've pretty much made it in the industry. Compton-bred rapper Kendrick Lamar has been bubbling under the radar since last year, when news broke that Dre added him to his 'Detox' album. Several other veteran MCs like Snoop, Kurupt and Game have all proclaimed him the "new king of the West Coast," and at 24 years old, with a handful of mixtapes under his belt, he just might be worthy of wearing the crown.
Frank Ocean
Just shy of releasing his debut, Frank Ocean's resume already includes work with Beyonce, Jay-Z, Kanye West and Nas. Not bad for a singer-songwriter who was a virtual unknown just a year ago. Although it seems the more popular he gets, the more of a recluse he becomes, Ocean is the perfect cocktail of elusiveness and explosive talent. As a member of the Odd Future collective, the New Orleans native's music is not only genre-bending but unlike anything we've heard in a while.
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