I'm another Half-Price Books fan here -- probably the best game purchase I made there was getting (on one occasion) Mechwarrior 2 for $5, in the big box and everything, and (on another occasion) jewel cases for Ghost Bear's Legacy and MW2 Mercenaries for, I think $4 each. Those were two very happy days for me.

(At the same store I saw Myth: The Fallen Lords on the shelf for a while as well. I already have a copy of that game, but I was still excited to see it there and if I didn't already have it, I'd probably be mentioning that purchase right about now as well.)

Non-game related: a very nice black leather trenchcoat I bought from a Goodwill, in like-new condition. It was $40 -- ordinarily way more than I'd pay for a coat, but I always wanted a coat like that one, and knew that really high-quality coats of that sort would easily go for $200 to $300 when bought new. So of course I snagged it, and now it's the best coat I've ever owned! :P

Monty Python's Complete Waste of Time and The Holy Grail

Got both games for a couple bucks, I was quite happy. :)

Oh, now and then I stumble upon a good book or record. Yes, I still buy records!

You're not the only one.

I'm always on the look out for new records to add to my Grateful Dead and Johnny Cash collection. :)

It's an Inquisitor avatar, I think? Anyways I can understand why he chose it, it's cool!

Today:

The Sims 1 complete (all expansions) - $1.50
Riven - $2
Star Wars: Empire at War Gold - $3
The X-Files game - $5
Wing Commander: Armada - $8
Police Quest: Swat 2 - $5

25% off, it comes down to a total of $19.65 (I don't remember the exact prices, the cashier input the prices in weird).

They are all complete, boxed copies (where applicable, of course). I can provide pics if you guys want, I'm too lazy to do it right now xD

BAA-OOMP

Found GTA 1 for PS1 in mint condition, paid $2 for it and sold it for $50, I never was much for GTA anyways, but knew about the value :D

Try google, I bet it can find alot for you.
I don't know about US, but around here we have alot of them.
6 in the city where I live, and that's without taking the used book/music stores into the account.
Just find stores that sell used items, I bet you that some of them will have games too.

Sold it on ebay?

Yes, best place to sell stuff.

The Great Escape = $1.99 at Walmart

Not necessarily a 'thrift' store per se..

A friend of mine owns a game store.. and sold me a brand new PS3 for $30.00 because he thought it was defective.. it turned out that he was running it with standard AV Cables and had it configured to run through HDMI and was getting no picture and audio..

As such I ended up with a brand new PS3 for $30.00.. this was 2 years ago and I still own it to this day and game on it quite regularly.

For me the best wasn't even a thrift store it was at an office depot clearing back stock and a copy of Star Wars Battlefront 2 for $3 just about 2 weeks ago.

If we include online shopping, I just bought a bundle a few weeks ago that included all 5 "Men of War" series titles for like $3.63 or so with the game's regular price on Steam for all titles topping in at around $150 with all the stuff in the bundle for around 98% off. Pretty good deal.

Also, many years ago when I was living paycheck to paycheck I would seek out the best deals I could find and use coupons and other discounts and would hoard them as it really helped get by. I had accumulated a whole bunch of coupons for $1 or more off on "Uncle Ben's" rice/pasta products with no expiry dates. 2 local stores both had Uncle Ben's products on sale for 50% or more off, and both stores had store coupons for additional discounts. My coupons were manufacturer's coupons and most people (and even many grocery/department store clerks) are unaware that you can use both manufacturer's and store coupons at the same time (get a manager to approve it if needed) so alltogether I saved something like 95% off on Uncle Ben's food that day and I got over $200 of groceries for like $10. I was walking so I drove it all home in a shopping cart which ended up in my storage room for a year or so with this huge pile of Uncle Ben's rice, pasta, and sauces. My friends laughed at the pile of it and everyone started calling me "Uncle Ben" which lasted for several years until it eventually wore off. :)