Local law schools have clinics for people without the resources to pay. It would be worth checking one of them out. Good luck!
I know this is an old article but, here is some good information:
You can file a provisional patent for around $300... This is easier to write than a non-provisional patent. But, it doesn't give you a patent, it isn't even read by the patent office. What it does is give you one year to file a non-provisional utility patent and when you do that, the filing date on your patent will reflect the filing date of the provisional patent. The other benefit is that you protect yourself when you go after investors because you can legally say "patent pending".
Be VERY careful about telling ANYONE about your idea. This includes friends, co-workers, etc. Not because they will steal your idea but because it starts the clock rolling on your patent - you only have 1 year to file a patent after you've disclosed it.
Also, don't publish in MAKE or any other magazine. If you do, when you go to get the patent you will be denied because of prior art. Yes, your own article will be considered prior art and you won't be able to file a patent.
Also, don't publish in MAKE or any other magazine. If you do, when you go to get the patent you will be denied because of prior art. Yes, your own article will be considered prior art and you won't be able to file a patent.
IIRC publishing your own idea starts the clock ticking and does not disqualify you
from getting a patent (unless the clock times out). After that it is prior-art for
everyone.
(* jcl *)
AlphaBeta:
Yeah I was just going to say that! It is the easiest thing you can do, and the post office time stamps make it legal. Definitely do it.
I have 5 various patents in science and design. It is practical to patent something yourself (although mine are through other companies), buy some decent books from amazon.
Just remember 90-95% of all patents just sit idle and go nowhere and when/if you do patent this idea make as few claims as possible but make them as broad as you can.
good luck!
jluciani - You are right, I just verified. If you publish your work, that starts the one year clock ticking. And that's one year for a non-provisional patent (the expensive, full patent).
And, as jluciani pointed out earleir: Mailing it to yourself doesn't do anything. It only proves that you mailed yourself something - not what is in it. It will not stand up in court.
Here's something everyone should do and it's really easy: Buy a composition book when you get an idea. I have dozens sitting in my house, some pocket sized and some full size for the "big" ideas.. 
The book can not have removeable pages or a way to add pages to it. You then start on the first page and document your idea - fill the whole page, don't leave any white space - no margins, no header/footer, etc. If you have white space, draw lines threw them so you can't add anything later. Date your work in the book. Every few weeks, have someone read your book - it has to be someone that can't profit from the idea - a co-worker, friend, someone in a club you are in, etc. NOT family. They need to read what you wrote and be able to understand it from just the notes - then they sign and date the book.
The US is a first to invent, not first to patent country. So, if you can prove you invented something first, it's yours to patent. The comp book is a good way to prove it (mailing it to yourself isn't). If you want to be extra careful, get the periodic signatures notarized.
Good luck. I hope you change the world!