If I did get lucky and see a gem amongst the crap, that's why I'd do too, it's just people at flea markets usually know what they're selling since they're paying to be there.

Garage sales on the other hand, a person could just see a box of old video games, comics, whatever, and say $0.25 a piece for them because they're just trying to get rid of junk.  I'm sure you would have to go to a lot before finding something good, but I imagine when you find something it's worth your while (and then you just have to worry about the ethics of ripping off a random person ).

ICOs noth worth much. I run a small used game store on Amazon. Dealing with anything not current gen. Most expensive game I've seen come through my store is Skies or Arcadia for Dreamcast. That can fetch at much as $90-100 depending on the condition. I've also had Action 52 for Genesis come through which will net you $80-90 just for the cartridge. Of course.. I kept Skies of Arcadia for myself :D

I'm still kicking myself for selling my copy of The Twin Snakes back to GameStop. At least I had a chance to play it.

Here is a list of games that will fetch quite a bit of money. I apologize for any repeats.

Burning Rangers (Saturn)
Dragon Force (Saturn)
Shining Force III (Saturn)
Guardian Heroes (Saturn)
Suikoden II (PS1)
Shadow Hearts (PS2)

And of course...

Panzer Dragoon Saga (Saturn)

A single disc for Saga can go for $75 on eBay.

So annoyed I threw away all my SNES / N64 boxes, had some proper gems - Terranigma, Metroid 3 (Big Box edition), Holy Magic Century, Legend of Time, Secret of evermore.... still got the cartridges at least, some of which are worth a bit.

Got some decent PS1 / PS2 games all boxed with instructions too... Breath of Fire III, Shadow Hearts 1, FF7/8/9 black label, Legend of Legaia.

I had a pretty good gaming life growing up :).

An actual snes copy of the original american release of Earth Bound is worth a cool $100-$200. Without the case and booklet.

If you can find it with the original box, case, booklet... hubba hubba. At least $500

http://www.ebay.com/ctg/EarthBound-Super-Nintendo-1995-/4585?_refkw=EARTHBOUND&_pcatid=2&_odkw=earth+bound&_pcategid=139973&_osacat=0&_dmpt=Video_Games_Games

I think a new copy of Madden NFL 13 is worth like $60

Which will be worth $5 in a years time.

Pikmin 1 and Pikmin 2 can be sold for quite a lot. And now that Pikmin 3 is coming out you could get more for them!

Thanks, Antiques Roadshow. It was a joke. 

cartridges for the NES, SNES and N64 are appreciating in value and can be valuable collector items. Unopened rare games are worth lots of money.