We bill on a monthly basis. All documents processed within a billing period are billed according to these volume tiers.
For example, if you process 65 documents in a billing period, the first 5 documents are free, the next 15 documents are $1.90, the next 30 documents are $1.60 and so on.
Check out the examples on the left that illustrate monthly fees based on the number of documents processed. The examples include the credit card billing discount and assume no interconnect fees.