I've read a couple of things that are coming up and may answer this question once they're released, the PayPal Pro (which I've installed and will start messing with) for one.
My question: is there a way to create a "credit system" so that people purchase $1.00 (for example) and then each post costs them 25¢? So $1.00 could give them 4 credits and each post use 1 credit. (again, for example)
I would really like this to work on comment fields too... but would be happy to start with main posting forms.