I second the recommendation to write/file patents yourself vice wasting money on lawyers. As implied, you generally won't be succesful selling an idea without a decent demo prototype, so dont fall into the trap of thinking the patent is the end-game. If you do consult a lawyer, I suggest thinking twice before filing any foreign patents (assuming you're outsie of the USA). If found foreign patents to be a major money pit, which pobably isnt worthwhile unless you've invented something like, say, "the wheel."

For patent images, you can do just about everything in PowerPoint and Sketchup.

Lastly, if you do file yourself, note that you can file your first few patents as a micro-entity, which lets you pay a little less. Don't forget however that ther are mainennance fees down the road though after the non-provisional is published. These can be a shock if you're not expecting them. Here's a rough summary of small entity USPTO patent lifecycle costs.if you file yourself (its a little cheaper for micro), details may vary slightly:

1. Provisional Filing - $130 ______________ (after 1 yr file non-provisional) 2. Non-prov. Filling - $140 3. Utility Search - $300 4. Utility Exam - $300

Total non-provisional fees (2-4): $800 ______________ (after ~2yrs patent will issue) 5. Notice of Allowance (i.e. issuance) fee: $480 ______________ (Maintenance fees over patent's life) 6. @ 3.5yr: $800 7. @ 7.5yr: $1800 8. @ 11.5yr: $3700