I spotted a ridiculously good deal on Space Invaders Extreme. It's normally priced at $19.99 and GoHastings has it for $4.96 New. It looks like it's listed as OOS on their website but you can still pick it up through Amazon.
http://www.amazon.com/gp/offer-list...p?ie=UTF8&qid=1270598670&sr=8-1&condition=new
http://www.amazon.com/gp/offer-list...p?ie=UTF8&qid=1270598670&sr=8-1&condition=new