Anyone know how much a guide licence is for texas?

Fresh water is $132.00,you can buy it anywhere you buy your normal fishing/hunting license. It is good from sept 1 to aug 31.

Any requirements besides the ability to fork over $132?

none

Unless you are on lakes that have additional requirements. Some lakes require permits and insurance from the water authority or even a USCG captain license. Check your lake.

If you guide, your regular boating insurance will not cover you or your boat or customers on days that you take a customer out. You must have commercial insurance. IF you try and do it on a recreational policy and something happens and a client gets hurt, you are screwed.

As Capt JR Howard mentioned, you have to know the lake rules for wherer you are intending to fish as fines and penalties can be stiff.

Also, you get the ticket even if a client puts an undersized fish in the cooler.

Guiding is not recreational boating that pays. It is a business.