I got an authentic Papa Smurf figurine for 500 bucks back in 2000. The figurine was made in 1972 and featured Papa Smurf incorrectly wearing a yellow hat, when in fact he wears a red hat! Oh my! This tragic mishap of Papa Smurf folklore is now worth well over 525 dollars. Looks like I made out like a bandit.
Ebay is my addiction. My ebay feedback is almost 700 now. Most is buying (adding to my baseball HOFer collection). There might be a few cards that I paid $50 for that are now worth $100 but I bet most cards have remained the same or dropped slightly. I'm now into graded tobacco cards (mostly T206 cards) - I have a very patient wife. I keep telling her that one day I have purchased 6 cars on ebay. One I bought back in 2002 that I'm still driving. The Edmunds trade-in value was $4k above what I paid for it. It will be my son's car in a few months so I'm looking again for number 7. As far as selling, I've had great luck. I really like BINs. I put a BIN on a used WII system a few years ago that grossed me $700 (it had quite a few accessories and a few games). It was the highest sold WII system sold in the Christmas season of 2007. I once had a N64 soccer game cartridge (with blockbuster rental stickers and stamps all over it) sell for $22 when 2 people got into a bidding war. A much better condition of the same game was also for sale with a BIN for $3. I felt bad for them because I knew that they overpaid. And I'm always amazed at what people will pay for broken stuff. I sold a broken PSP for $40 a few months ago. Broken cell phones for $30. Unlike shipwreck, I always state totally accurate condition description. I've been ripped off a few times and I would never want my buyer to not be 100% pleased with a purchase from me.
Shipwreck, was it an original Whammy I? If so, I can't hate too much since they normally go for $400-500. If the buyer can fix it, it's a great deal. If it's a reissue, you're the biggest douche ever!
I purchased a very large lot of 1988-1990 starting lineup "commons" for about $2 a figure. When I got the lot, it actually had several very rare regional figures that often sell in the hundreds on Ebay, including some rare 1989 football and 1988 basketball. I also purchased an original Star Wars style "A" poster as "damaged", but the guy couldn't find it when he went to ship it so he sent me an almost mint one (rolled, not folded, which is much harder to find from that era) instead. After carefully investigating the poster, I determined it was an original (I collect vintage Star Wars posters, so I know what to look for) and it was worth probably 5X what I paid for it.
I once bought a Sirius boombox for my dad's Sirius radio. Turns out it was the wrong boombox, and I listed it on Ebay and actually turned a profit even after Ebay's fees. That was awesome. I made a killing selling 10th anniversary Tickle Me Elmo. I was working at Wal-Mart at the time and bought them up when we put them on sale 2 days too early. I got a 10% discount, and sold them for triple the cost.