A patent can cost several thousand and up, depending on several things. Go on the US Patent Office website and check out the procedure.This is a good place to start
http://www.uspto.gov/main/patents.htm . You may or may not want to hire a patent attorney.That will depend on how much research and all is required. Your telling the patent office that nothing like it exists won't do.I have been involved in creating tools that were patented, and a jewelery clasp. The clasp cost about $9000 to get patented, and has not yet gone into production. We have a manufacturer that is interested, but these things take a long time. From the beginning to making any money can be 5 to 10 years often. Sometimes the only way to get it made is to set up manufacturing yourself. That can cost from a couple thousand for a very small scale home shop to millions to set up a very small factory.
The questions to ask are:
What will it cost to patent?
What will it cost to manufacture (start up costs, material per unit, etc.)?
How many units will I reasonably sell in ten years?
Will it create repeat buyers (a big plus if the item is a consumable)?
What profit will I make from each unit?
If the last three will add up to more than the first two then you have an idea if proceeding is practical.
The other option is to get with a patent developer and get a percentage of the eventual return. If they want you to pay them any amount up front, they are not who you want.Before proceeding to this step do the things required to protect your intellectual property from unscrupulous developers.Before giving any details about the item, throughly check out the patent development firm.
I hope this pans out for you. Remember, someone invented the can opener - 2 cents to make...200 million sold at $1 each.Also, the simpler the invention, the more likely it will sell.
Good Luck.
Stacy