I want to pay off my community service hours in with money instead of serving it
You'll have to get your case back in front of the sentencing judge for a modification of your sentence. If the judge grants your request, they will convert the hours of community service into a fine.
If you're looking into this, you need to do this BEFORE your community service is due. If you're already beyond when it was supposed to be done, they may not allow this modification and - worst case scenario - they convert your community service to jail time and you go into custody.