i've sold a few beats got good money for them too(bout 400 each)but they were not copywritten so i basically relinqueshed all rights to the purchaser,come up with a few prices a cheap one for people who want to use your beat for demos or to flow on,but not for resale,then have a substantially higher price for an exclusive beat,one that they can use for resale(as a finished product with lyrics not as just a beat)get everything legal use contracts,as for how to sell,there is nothing you can say to people to convince them,the only way they are going to pay money is if they're serious,if they're not willing to pay a little extra for quality,then they're not hungry enuff,tell them come back when they're serious after they blow there money on some whack beat they got free with studio time,untill then stop wasting your time,ask them if thy would sell their rhymes for 20 dollars