A fews months back, I started on the journey of selling my pin collection on Ebay. I have about 450 Tinkerbell and Mickey pins, mostly LE and the hard to find. I stopped selling because I found that the cost of selling, which includes the listing fees and sales fees, as well as the cost of overhead made it all seem pointless. I'd rather give the pins away than feed Ebay, and probably will do just that on my upcoming trip at the end of July.
Some of my observations:
1. Selling single pins is far more effective to recoup what you paid.
2. Selling pins in lots attracts more attention, but most collectors might only be looking for one or two of the ones you have listed. If you're selling the official traders, then this is the best way to go since buyers are just looking for quantity to trade at the parks.
3. It's a yard-sale. Most people are looking for bargain basement prices.
4. No matter how much I was losing, I found it disheartening to receive low scores on shipping costs, when I was actually losing money on it.
5. I honestly don't know how the large volume sellers stay in business. With the risk of low ratings (because someone just feels like it and it's anonymous) affecting your selling costs, I'm surprised more just don't give it up.
6. Sniping is a good thing when you're buying, and bad when you're selling!