I just went to webmd.com and typed in "missed periods not pregnant" in the search box. It came up with a great article that gives a really good explanation of what MIGHT be happening that's causing you to skip your period. You can also look for doctors on the website (there's a link near the bottom of the page), and from there you can just call the offices that are near you to ask what their fees, etc are. Other than that, I'm sorry to say that most dr's are requiring insurance benefits, because without the money that our health insurance pays them, they can't pay their malpractice insurance (and believe me....it's more than you could ever imagine!!) Malpractice insurance rates are also the #1 reason OB/Gyns are going to other areas of medicine, or leaving medicine altogether.
Anyways...sorry to get on my soap box about insurance...I hope this info helps! :)