Just do a search. There are TONS of threads on ebay lowers and stuff. Try searching ebay lowers and you should find pics and info and everything you need.
I researched awhile back and the ones on eBay sold by sellers tmshelmet & Mutazu seem to be popular. Lucked out and found set on some used OEM's from member on here.
I've gotten 2 sets of the cheap eBay ones, with mixed results. The first set fit together very well. All the pieces lined up flush. The second set no so much. Same seller, same part. So its a roll of the dice.
Im only leaving mine on in the coldest months, so the function is more important than the finish.