I am using a GPS module connected to a microcontroller with wifi and bluetooth but no cellular module, are there any microcontroller recommendation with cellular modules or are there any recommendations for cheaper cellular modules.
Integrated, no, I don't think so.
SIM800L is a low-cost cellular module that's popular in DIY projects. Keep in mind you need a cell network subscription and SIM card to be able to communicate.
Perhaps tell us which microcontroller you have and what the application you want to build actually is.