No fixation
There is no fixation with Quickpay. You can cancel your subscription at any point before the end of a quarter, and then you "avoid" getting another bill for next quarter.
For example if you cancel your subscription 31.12 you account would shut down 01.01 and you would not get a bill for 1st quarter.
This combined with first quarter for free makes it completely riskfree to try out Quickpay for as long as 3 months.