As you can see from the above responses, and also in my experience it seems like Chiropractors MO is to fix you up about 70% the first day but lay the story about how you've been like this for so long you really need to come back and see us 3x a week for a few months to get you right and then we can back it down to a maintenance mode... or you'll just have the same problem again. That makes sense, but, you have to realize they are going to push for as many visits as possible and you need to determine what you can afford and try and balance that with reality.
In my own experience, it did make a difference the first few times I went (I gave it a month, with 3 visits per week the first 2 weeks and then 2 after that),. Near the end it wasn't doing much for me (I felt about the same before/after) so I stopped. . My insurance covered most of the costs, but, even with a smallish copay, say 10-15-25/visit it adds up quick when you are going multiple times a week.
My wife also went because she's had neck pains forever. She stopped going for a few non-medical reasons. Just recently she decided to go back again. She was in quite a bit of pain (in her neck and back) before she went this round and after 3-4 visits now she seems to be doing a lot better. Our copay is closer to $30 now so it's a lot but:
If she went to a doctor they'd have seen her (1 copay) requested some xrays and other tests (another copay) scheduled a followup visit (another copay) prescribed some drugs (another copay) maybe recommended a specialist (another copay) etc and it still might not have done anything to actually fix the problem, just manage the pain. So it costs money either way, but, I think the chiropractor is better in her case. YMMV.