The most important thing in the chain is the instrument and the player. That being said, don't skimp on equipment if you plan on doing recording and getting decent results, especially if you want to do it as a service.
You won't always get good musicians, so good gear to make up for the bad musicianship! Mics that everyone has are generally mics that are worth their salt. SM57s, RE-20s, MD421s, SM7s, Beta52s, all excellent 'industry standard' dynamic microphones that will allow you to mic not only drums but pretty much anything else.
There are gems that aren't expensive that you'll find to be uncommon, but they're not always going to work for you. I love ATM25s and low-end CAD mics but I'm not a reputable engineer and that may be why : )
In the end tough, buying shitty mics for a project is POINTLESS longevity-wise. Get the best stuff you can over however long it takes. In the end, if you can borrow something and make it work, you'll be MUCH better off.