What will most likely happen if I plead guilty to a misdemeanor for simple possession of marijuana?

The maximum penalty for a misdemeanor is $1000/ 30 days incarceration. There are many procedural ways to defend a simple possession charge starting with how was the offending substance found in the first place? Was there reasonable suspicion? Lawful search and seizure? Etc. There are also alternatives to pleading guilty. This is not something you want on your record. It could follow you if you apply to the military, jobs, etc. Retain an attorney. A misdemeanor defense shouldn't be too expensive and it will be worth it down the road.