I guess you've tried Craigslist?
Never thought about SummitRacing.com....or Jegs.com...or TireRack.com...or 4wheelparts.com....or Quadratec.com(jeep site)....or eBay.com...or shoot, even your local wheel and tire shops?????
If you're wanting cheap, you'll be best to look into steel wheels. Roughly $50-75 each. As you mentioned, ProComp Series 52 is what I ran on mine when I was steel wheeled.....15x10 w/ 4" backspace. Not expensive either....rather cheap. And no stupid painted/sticker stripe on the lip.
Best bet is to look at wheel manufacturer websites and see what you like and check the specifications to see if they make the size and bolt pattern you're after. Simply making a post saying you're looking for 15x10's doesn't help at all.
Help me find a good tire/wheel combo for 15x10 wheels!