Metered Internet / hot spot style

Hello,

I am currently managing shared accommodations for young people and want to use the Internet as an incentive somehow. Ideally I would like it to be set up like a hotspot to where you will be able to purchase/earn limited time on the Internet (eg 24hr, 1 week etc)

I would like to usey own router obviously but is there anyway I can do this using some kind of software or anything?


Thanks,
Aaron