So, I go around looking for this and that quite a bit. Some of my most recent purchases:
Ebay: Phantasy Star II, Alex Kidd in Miracle World, Vectorman 2, Marble Madness (all genesis) - $8 including shipping for all four combined. All of them look pristine and play great except for Phantasy Star II which has obvious wear and has to go in just right to play, but they all do still work and PSII saves after all these years.
Amazon:
Chuck Rock II complete in box: $4.00 (VOID VOID VOID sticker on top of cart but not on label, easily fixed). Box/Manual in great condition with hangtab.
Aero The Acrobat Boxed: $5.00 (cart turned out to have a pretty bad label with a large tear, but box is fine. I'll have to replace the cart sometime.) No Hangtab.
Rolling Thunder 3 Boxed: $6.50 (great box, great condition game and label with a few VOID VOID VOID stickers on the sides not touching the label - some googone should resolve that. No Hangtab.
Cash Converters (today):
Road Rash II (Genesis): $2 (Cart looks good, plays great)
Gargoyle's Quest (Gameboy) - $3 (fairly hard game to come by and gets pretty pricey for a gameboy title, needless to say I snatched it up when I saw it)
Christmas is coming so I'll likely get a bit more for my collection soon. Here's to great finds, and great prices!