I wanted to update and Bump this thread as I've been doing a little research on where to get one for free, and am about to get my free one scheduled.
I went to a Planned Parenthood in Sioux Falls SD and they told me they had nothing to do with them, so I caution you against relying on them even though their website will say they offer "Men's Services". Call ahead
A former member of this site had his done thru them in Portland OR but I believe only the consultation was at PP, the actual surgery is at a contracted urologist generally.
The simpler way, I found, is to get one funded thru health insurance. Most state plans will let you get it completely free.
Under the age of 21 you should be able to receive Medicaid (free insurance) in many states, also if you are disabled and over 21 (or over 65). Under 18, you probably won't be able to have the vasectomy paid for, however. Over 21, you have a few states to go to for free health insurance. Simply list your address as "Homeless" and apply for it at the same time as your SNAP(food benefits). It'll probably be the same form, just check an extra box.
Washington state has not only free health insurance, but a specific family planning program called "Take Charge" that will fund your vasectomy. This is the option I'm pursuing.
Denver CO-You can get one funded thru Tri-County Health Dep't
Orlando FL- Marion County Health Dept pays for them
MOST STATES DO NOT HAVE FREE HEALTH INSURANCE IF YOU ARE 21-65 AND NOT DISABLED OR PREGNANT. You need to do your research on this one.
I got insurance in Oregon a few years ago, but they now have a waiting list.
Massachusetts has free health insurance, they are a great option.
Wherever you have it done, it'll probably have to be in the state your insurance is from, and there will be a 30-day waiting period. First your consultation (real quick and they give you some glossy pamphlets) then a month later the real deal.