This. T-Mobile will give you a free trial too if you’ve got a modern phone - 3 months to test out their network alongside your existing carrier, with no contracts or whatever required.

Verizon doesn’t offer a free trial directly, but Visible (a prepaid brand of Verizon’s) does.

AT&T doesn’t offer one either, but you can get a cheap SIM for a month from someone like Boost (make sure to use my.boostmobile.com and not www.boostmobile.com or you will get T-Mobile) or H2O.

Given how much these providers ask for every month, it’s worth spending a little time to make sure you’re getting good value for your money, IMO.