It's a contract company that usually sells these "blocks" of flight time, and it is usually to international students that are trying to meet some airline mins in their country.

Ameriflight makes extra money by utilizing this FO program too.

Disclaimer: I am not advocating buying time. ($50/hr is pretty cheap). Just wanted to clarify that it may not be that company selling time directly, but a third party who is selling flight time, then contracts it out to these Part 135 companies.