Not sure what you're looking at as cheaper. I just got a Canon SLR for $409 just before Christmas, that was a fantastic deal for me, brand new. It's my first SLR, I have not wanted to spend the $$ but am way to picky about my image quality and I'm not getting it elsewhere.
But anyway, I have bought a couple non SLR's from eBay, used and refurbished, and I'll never do that again. I did well with my first one, about 3 years ago. It was a Kodak z710 refurbished, takes great pictures, 10x zoom LOVE it. When it started having focusing issues late summer we started looking. I bought another z710 (after returning several supposedly great top of the line cameras to stores) also refurbished. NOT as good. The pics are as good, the camera seems slow, I just wasn't happy with it. We picked up two used cameras, another smaller Kodak (for DS) and it was fine for a 6 y/o, not for me. Served it's purpose, but not pleased at all with it myself. Then I got a used Exilim on eBay. TOTAL waste of $$$$. It's going to DS3 since he's been watching brother and mom and wants one. It takes worthless pics, no matter what we do they're blurry or fuzzy. It worked well the first 2 months I had it, then went bad.
IF you are going to go the eBay way, I'd say make sure it's NEW and worth the risk. $400 wasn't really in our budget, but it was a very good deal I knew I was getting something new and worth every penny. I wouldn't expect to pay any less than that for one on eBay. But again, I'm not sure what kind you are looking at or what budget your are trying to fit in. (I'd also seen deals before the holidays as low as $300 on some lower brand SLR's)
Good luck, I know how frustrating making the switch, debating on the cost and all is!

