Do you have to pay for gps and or cellular

The Apple Watch shares the iPhone's phone number, and the carriers that support the Apple Watch charge a monthly fee. In the U.S. the fee is $10 per month. Here is a list of carriers that support the Apple Watch:

https://www.apple.com/watch/cellular/

The GPS only Apple Watch can do Everything the Cellular model can do AS LONG AS your iPhone is nearby, where nearby is generally somewhere in the same moderately sized home. The Cellular model allows you to leave your iPhone at home while you go for a walk, run, bike ride.

And as mentioned, GPS is free, paid for by the government(s) that put up the GPS satellites your GPS service is using.

No you don't have to pay for GPS

Cellular you need to pay your carrier for yes.