I've made serveral purchases on Amazon, but I've never sold anything there. I am selling a few of my personal ps2 games on ebay and decided to list one of them on Amazon just to see how it worked out.
There are no fees until the item sells and most items do seem to be listed at higher prices than ebay. They give you 30 days (with free account) and if item doesn't sell you can relist it.
The prices may be higher but so are the fees once the item sells. They charge a .99 cent transaction fee, $1.20 listing fee plus somewhere between 5% and 15% of total sale depending on the item (%15 for video games).
Shipping charges are pre-set. This could be good or bad depending on the item. I don't think it will cost $3.49 to ship a video game via media mail.
I guess volume of sales and profit just depend on the item/product just like anywhere else...except ebay. Of coarse, a zero feedback isn't going to help.