Internet Hotspot works on time limit

[Eddie D]

Hi

Looking for a solution to create like an internet hotspot that works off a token ( voucher)

guests have to enter printed voucher number and are then allocated a time limit to use the computer before getting locked out .

Is there a free package available or router firmware that does this?
Not interested in any online billing system ….all that I have seemed to have come across.

Any info would really be appreciated

Tks

Ed