That is how most toll systems work. You load up a balance on the card $10/$20 and it deducts every time you cross a checkpoint.
The difference between this and a micropayment platform would be the fees. In the toll system, the fees are paid once. With a micropayment platform, the fees would be per transaction.
There can be a "self hosted" version of such a platform that say each content-provider can host but I am not sure it will work out against the cost of maintaining it includes much more than just hosting (securty, auditing, refunds, taxes etc).
The difference between this and a micropayment platform would be the fees. In the toll system, the fees are paid once. With a micropayment platform, the fees would be per transaction.
There can be a "self hosted" version of such a platform that say each content-provider can host but I am not sure it will work out against the cost of maintaining it includes much more than just hosting (securty, auditing, refunds, taxes etc).