[CarlLester]

We (well my wife did most of the work) went through this a year or so ago. I don't know all the details, but here are a couple of things I remember:

1. If you have a prototype, do not show it to a lot of people. The invention we were seeking a patent for was created by my father to assist him in his daily work. He's had it for a few years and has showed coworkers as well as sales reps. The patent lawyers immediately considered that a bit problematic. They figured they could probably get around that by explaining it as 'market research' or something like that.

2. Patent lawyers will sit with you for a free consultation to go over your options. And there are options which cost different amounts of money depending on whether you want to do a full patent search, etc. (This is the part where I cannot remember all the details. I do remember that one of our options was going to cost us a couple thousand dollars and the more extensive option was going to be many times that)

3. The patent lawyers we sat with showed us that Google has a good patent search function. They recommended that we start there before committing any funds. Maybe you have done that step already but just thought I should mention it.

In the end, we felt our product was not unique enough to warrant spending the funds to pursue further.

Edit: See Tron_fdc post below. It contains some of the details missing from this post.

Good Luck!