This thread reminds me of something I've been wanting to ask for a long time.
For those not in the business/startup/technology world, there is a company in the midwest that is making huge waves in the online payment world. They're called Dwolla and they're really getting popular. The basics are that they work through connecting your account to your checking account, and then you can pay and receive payments all day long. The payer pays a flat fee of 25 cents and NO other fees beyond that. Transactions under $10 are completely free.
Downsides:
1. No credit card protection.
2. There is no real buy/sell protection policy, if you believe in that sort of things.
3. Not everyone is using this right now, so there's a process for people to sign up, link up your account, etc.
Upsides:
1. The fees are obviously ridiculously low.
I think that this payment system is perfect for private party transactions where you have some degree of trust between the parties (e.g., on the b/s/t board amongst known sellers).
I would love to see something like this adopted by collectors. Dwolla's website is here, if you're interest in learning more:
https://www.dwolla.com/
Miguel