I have an idea for an invention, but I have talked to a few people who say that the firms that advertise on TV and radio promising to help you with your inventions are really just scam artists. Would it be better for me to do the research and everything else involved myself or go through a third party>

Call, or better, visit your public library's reference desk and ask this question. You may end up making copies and/or checking out a book or two. There are books to lead inventors through the prototype-making and legal process.

I'm a librarian (home on extended sick leave) and know that libraries have specific information to help you so you don't get scammed. If you don't find out exactly what you need, please return here and somehow get my attention so I can do my best to point you in the right direction.