350K+ Just an estimate...this is the most volatile group in terms of budgets... because you have guys like Dan Smith that have a million+ payroll for a decade and only one-two wins to show for it... (Due to terrible leadership/coaching, etc.
AA, A - anywhere from 60K to 350K
You can get by on less if you have a "regional A" team but in order to be able to recruit and offer some of the perks...you need a bit larger of a budget. Some of the best "AA" teams in the past few years have not been "BIG BUDGET" teams... little known fact
B - minimum 25-30K, most of these teams are regional, and some are very very good.
Can it be done for less? Absolutely.
Is that common? No