Ebay is tough but there are a few sellers that do well on there. The key is to develop a customer base who faithfully bid on your auctions. This takes time and you'll have to sacrifice a lot of decent domain names to build that customer base up to a decent level.
By sacrifice, I mean listing a good domain name and only getting $11.25 for it, minus the Ebay fees. Other times you might only get $1.25. That's happened to me many times. I also get $30, $50 and $100 sales. It all averages out.
Essentially, you break even, but, since you've gained a new customer, you're actually ahead. Repeat this enough times and your customer base will grow enough to become profitable.
That's how I use it. It's kinda like a "loss leader." If you've ever worked in retail you probably know what I'm talking about.