Flea markets can rule. Illegial immigrants are a great source to buy old consoles from.
I picked up a Castlevania SOTN non greatest hits from a flea market in great shape once for like $5.
Then there was the FFII, FFIII, Earthbound, Secret of Mana, Secret of Evermore, Mario RPG, Chrono trigger all complete for $55 incident.
When I saw them lying on the table I started shaking and almost wet my pants as I got my wallet out. I had to borrow like $10 from dad which was embarresing since I was like 28 at the time (plenty of cash in bank but not on my person).