I have quite a bit of this. I had a PS3 for awhile, and while I liked it, I began to feel increasingly guilty that I paid 400$ for a video game system when I already had a Wii that I like. So I resold it on Ebay for about 90% of what I paid.
As for games, I recently did the buy 2 get the 3rd free thing with a Toys R Us Sale and got 3 DS games, Scribblenauts, Mario and Luigi 3, and The Legendary Starfy. Scribblenauts is the only one I like. For Wii games, I really like platformers, so I had high hopes for both Wario Land: Shake It, and de Blob, the presentation in both was very good, but I did not enjoy the gameplay and sold them both.
I'm sure there are a lot of other times I've done that, but those are the ones I thought of off the top of my head.







