Just a quick look around:
PayPal - 2.9% + $0.30 USD (somewhat less for big items)
ProPay, cheapest account appears to be $50/yr + (3.5%+$0.35) for visa/mastercard, no pct for amex & discover. This is really only a solution if you are a high volume seller.
Moneybookers - 1% up to $0.50. Costs nothing to put money in your account from your bank, but costs $1.80 to withdraw back to your bank. Also, apparently changing name to Skrill, which is an even worse name than Moneybookers, but that's not really relevant. Kinda jerky to put the fees on the sender, but at least the fees are way smaller than PayPal. They also have merchant accounts where the seller is paying, but those are more money.
Paymate - 3.0% of the value of the payment + $0.50 per payment (their US Ebay seller account) + $12.95 to apply for an account + $5 monthly fee + $39.95 annual PCI fee. So yea, really for merchants only.
So, of the allowed payment services, only Moneybookers is really an option for the occasional seller. The 'buyer pays' aspect is pretty odd from my point of view, I don't know that I'd want to deal with someone where I had to pay extra money to send them the money I owe them!
I just checked, and it appears that you can setup your Moneybookers account appropriately through Ebay, you can put it on your listings as easily as you can PayPal. I'm going to open a Moneybookers account and try a listing with it to see how it goes.