Sign up for a month and pay.
Immediately go and cancel the subscription. It will say the cancellation takes effect in 30 days, however they will actually cancel your subscription in 2-3 days and issue you a refund. In that 2-3 days you can watch Netflix. Repeat.
I’ve personally done it twice. Mostly was trying to actually sign up for a 30 day period to watch a show, but wasn’t planning on letting the subscription run unquestioned like I used to. The price is too high for that. Turns out Netflix is petty. Either you let the subscription run, or they cancel you.