So I sliced myself open trampsing around Brooklyn Census Tract 77, which reminded me I needed to get a tetanus shot, which reminded me to post my best advice about getting vaccinated if you're going traveling. And my best advice involves how to not pay for anything.
There is really no reason you should shell out any dough for travel vaccines unless you're getting something exotic, which pretty much means Rabies or Typhoid. There's some other exotic vaccines (did you know there's a vaccine for the Plague?), but they're generally needed only in very specific circumstances, or are considered ineffective for adults. I paid for Typhoid, but I wasn't working with wild animals , so I passed on Rabies.
Now, it might be that this is what my 3.2% NYC income tax buys, and the idea of getting free vaccines elsewhere is a dream. But if you live in New York, there's no reason to pay the 3.2% income tax and your doctor a few hundred bucks more because your insurance (if you've even got it) doesn't cover vaccinations. For all routine jabs, skip your doctor and hit your local health clinic. In New York, there's actually one in every borough except Staten Island and Manhattan, open from 8:30 - 2:30 Monday through Thursday. I actually can't speak for other places, as I always went to the one on 28th and 9th in Manhattan that's closed now, but it was great. I went a half dozen times, never waited more than about an hour and a half, never had any hassle and never had to pay a dime. Get a DtaP (Tetanus, Diptheria, and Pertussis) and/or an MMR (Measles, Mumps, and Rubella) if you need it, and begin a three-shot series of Hep B at least 6 months before you leave. If you're leaving next week, get the first one or two anyway and the remainder when you get back - that should be sufficient to immunize you for the length of your trip.
You can also get a Hep A, Meningococcal, Chickenpox, HPV, and/or Pneumococcal vaccine, which are supposed to only be given out to certain demographics they consider "at-risk." Meningococcal and Pneumococal I didn't think I needed, I've had the Chicken Pox, and the HPV vaccine is only for women, but I wanted Hep A. I was prepared to be an "at-risk" group if they asked me, but they never did. The first few times they said they were out, and the third time they sent me upstairs for the vaccine without asking me anything. Get there early and you've got a better chance. Hep A won't kill you, but it'll ruin your vacation. Hep A is a two-shot series - same advice as Hep B applies. I'm guessing this same general "don't ask, don't tell, smoke em' if you've got em' " deal applies to other vaccines also. It's not like the "at-risk" categories are super-narrow groupings where the clinic will require some kind of proof or documentation. For instance, just being a smoker puts you in the "at-risk" group for Pneumococcal, and being a gay male puts you in the at-risk group for Hep A.
Another one you might need is Yellow Fever, depending on what country you're going to (Yellow Fever is endemic to Tropical South America and Africa). This actually has it's own certificate, and is a required vaccination in some circumstances. The thing is, countries that require Yellow Fever vaccination only require it if you're coming from an at-risk country. And the United States is not an at-risk country. So head over to your first destination, and get a Yellow Fever vaccine there. In all probability it'll be free. I can only vouch for this method in Argentina, where it was as simple as going to the tourist booth and asking where I could get a Yellow Fever vaccine.
For more vaccine info, see the NYC Dept. of Health's Bureau of Immunization, the Center for Diesese Control's Vaccinations page, and the UK-based The Site.