Click on 'Pricing' then scroll down and expand 'Micropayments'
It's 5% + $0.05. So for your $1 in revenue only $0.10 is taken by Paypal.
The way I found to get on the program is to apply for the standard account, and then apply for the change to micropayments. In my case, they didn't tell me whether I was approved, the only way I could see that is by looking at their take on transactions.
So far, it's working great.
centipaid.com talked about having a scaleable micropayment solution.
However, almost any solution requires one to have money 'in the system' and earn/spend the micropayments, and pay a fee to take it out or put money in. There are a number of other providers that do this through stored value Mastercards, etc, but, those fees sometimes become prohibitive.
The way I've seen a number of companies handle micropayments was to keep the money in the system, but, you couldn't get it released without earning $25 which kept administrative costs to a minimum. You had to fund the account, but, if you didn't spend it all, you couldn't get it back. Facebook credits work in a similar manner - one purchases $x of credits, then can spend those coins on various apps.
Paypal Micropayments https://www.paypalobjects.com/IntegrationCenter/ic_micropaym...
Amazon FPS (automatically switches between micro rates and larger purchases) http://aws.amazon.com/fps/
Under pricing: 2.9% + $0.30 for credit card for transactions above $10 and 5%+$0.05 for credit card for transactions below $10.
It seems like social gold is more focusing on assisting a community or a large virtual world. I don't have that, but I do see they also identify it as useful for services. I guess I need to look more into it. I think what I will do is release my beta to HN and ask what they think I should go with. Ultimately some form of payment will be required, but I am not sure if I am approaching it in the best way.