Whilst it can seem quite expensive to buy a patent for something that is currently only an idea, it can be well worth it in the long run. For every invention, from vacuum cleaners to mobile ringtones, there has always been somebody left kicking themselves because they had thought of it first but were usurped by a company that is now making millions.
Patents are awarded by the government and give an inventor the right to stop others using, selling or manufacturing their idea without permission. This lasts for a limited amount of time, depending on how much is paid. Patents are often described as granting intellectual property meaning that they can be bought, sold or rented to others.
A patent gives you the right to stop others from making your invention, but it does not give you rights above anyone else to have your invention made. Once you have one, you will need to start thinking about ways to manufacture your idea.
The two main types available in the United States are Design and Utility. Utility patents are awarded for the invention or discovery of any new, useful and developable process, article of manufacture, machine or composition of matter.
If you have a new, original and ornamental design for an article of manufacture, in the United States you may be granted a Design patent.
Additionally, Plant patents are available to anyone who discovers and can asexually reproduce a totally new variety of plant.
The rules for awarding these property rights include the fact that your invention must be useful. This means both that it should have a purpose, and that it should be manufactured by normal industrial processes. An invention that cannot be fesibly manufactured could be rejected.
Abstract ideas, including laws of nature and observed or created physical phenomenon, cannot be granted patents. Neither can you be granted property rights over an idea or suggestion it is the actual invention or machine described by you that it patented, not your idea.
Sometimes you have an idea, but do not know it already exists somewhere. If other people in this country have known about or used your idea before you apply, you will not be eligable to have it patented. There are websites where you can check which ideas have already been granted a patent.
Furthermore, if your invention has appeared in a printed publication in any country in the world, for more than a year before your application, you cannot have property rights over it.
For more information, you may wish to look up the Patent and Trademark office of your government, which will highlight the full rules and procedure. Often, when people are sure they are eligable, they choose to hire a patent attorney or agent to help them with applications. Good luck!