Appliances!

Most Goodwills are contracted to get Walmart's discontinued appliances. These electronics are usually 50-70% off of their retail values and many have never even been opened.  I have found that most of the time the boxes are damaged but the products inside are in perfect shape.

A couple of weeks ago, I found this quesadilla maker for $7.99:

It retails at most stores for around $20. I've had a great time experimenting with it so far!