First, that would be theft in most countries. The proper action is to contact local carriers or the police.
Second, the highest rated would be Samsung. Reasonably priced would be eBay. $20 is fantasy. (Maybe for the digitizer, the "glass", but not for the whole screen.)
Third, since replacing the screen means using a heat gun to get the screen just hot enough to melt the glue without damaging the screen, and the difference between the two is only a few degrees, unless you've already done this a few times successfully, I'd recommend letting an experienced repair person do it - and the labor alone is about $50 is you're lucky.