Be aware there are prereqs for the NRA Personal Protection Outside The Home, and Personal Protection In The Home is a prereq for PPOTH. PPITH also has a prereq of proof of prior shooting experience. Holsters must also meet specific requirements.
The NRA still lists Personal Protection Outside The Home as having two levels. Approx 100 rounds are required for level 1 and aprox 115 rounds required for level 2 per the NRA website. You mentioned they suggest 150 rounds. Contact the instructor to clarify what the class is and is not. I would also take more ammo than is suggested.
The NRA does not have any requirements on class fees. Class fees are affected by range costs, insurance, NRA class materials, etc. Some NRA instructors also have part of the fees going to them as compensation for their services. Some NRA instructors do not take compensation for their services.