A lawyer shouldn't be all that expensive in your situation. Could you DIY it? Sure, but... The advantage of a lawyer, maybe even more than knowing the law, is that they know the system, including the judges and the attorneys for the state. This allows them to get you the best deal, at least if they are any good. Ideally you get this reduced to something that isn't drug-related. I'd either interview a couple of attorneys (phone is fine and they shouldn't charge for a short consultation) or go with a referral from a friend who has had a good experience. Make sure to ask what the costs will be upfront. Also, don't involve the attorney any more than necessary to give them the information they need. The meter is always running.
Good luck. It is BS that NY is still prosecuting such minor infractions.