You can save yourself between $400-$2,000 (and up) by doing your own patent search. However, you may need an attorney to counsel you as to whether there is actual infringement, and whether it is patentable. However, this step will go a long way.
Step 1: Go to www.google.com/patents
Just type in terms or any sort of words to best describe your invention. Add key features which may distinguish your invention over the others. Los Angeles Patent Attorney
Step 2: Download any available pdf's, if available.
Hopefully, the pdf will be available for quick download. If not, then you will have to go to the USPTO website
Step 3 (If necessary): Go to USPTO website: http://patft.uspto.gov
Type in your terms as you did with Google/Patents.
Set the Years to (1790-Present)
Start with the Title.
Then use abstract.
Proceed to the claims.
Use this process for BOTH issued patents as well as the published patent applications.