Ok so after reading this thread and other sites, I'm about to buy a Canon EF 50mm f/1.8 MkII from ebay, I can get one with postage for about $120 or so. I'm still kinda new at this whole endeavour, so is this what I'm looking for as a 'nifty fifty'?

Also could someone be so kind as to explain the concept of reverse mounting to me? Thanks in advance.