Honestly I'd say just find one on youtube. I've done this a ton, they're usually free and it works out pretty well. For finding the beat, just think of which artist would put out a song with that kind of beat. For example, something slower and more meaningful you would put in "J Cole type beat 2017", but if it was going to be a hype song you would put in "Migos type beat 2017" haha. Hope this is helpful