I have an idea of combining a number of already existing (and probably
patented) devices to serve a new function. Very little modification,
or no modification at all, to those devices will be needed. It is just
putting them together. Is it possible to get a US patent for it?

Also, when applying for a patent, do I have to provide a working
sample, or just a proper description will do?

And the last part - what would the entire procedure cost? It would
help if you could provide an approximate list of steps I have to take to
apply for a patent, and approximate charges for each step (patent
search, average lawyer's charges, etc.).

Hello sp1995,

Unfortunately, my research has shown that you are unlikely to be able
to patent a product that combines two other patents, unless you
receive express permission from the patent holders, and even then the
combination has to be such that it is not obvious. There is hope
however, perhaps the items were non-patentable themselves, or you will
be able to patent an accesory which combines the two devices (keep
reading):

"They say you can receive a patent for combining two elements. It may
be possible to receive a patent for combining two nonpatentable items
if the combination isn’t obvious. "As long as the combination is novel
and unexpected, there’s a good chance you can receive a patent," says
Mills."

The same article goes on to say:

"Receiving a patent for your improvement doesn’t mean you
automatically have the right to sell your idea. If your improvement
patent involves the use of an existing patented product you may need a
licensing agreement from the dominant patent holder. An improvement
that can be added to an existing patented product without changing the
original product is allowed; however, if you make or hire someone else
to make the original patented product with your improvement
incorporated into the design, you need a licensing agreement. It’s
always simpler, therefore, to make and sell an improvement as an
accessory rather than as a modification to an existing product." (by
Tomima Edmark)
"Inventions: The Next Generation"
http://www.gwsae.org/ExecutiveUpdate/1999/December/ElectronicIssue/innovation.htm

If it would be possible for you to sell your item as an accessory to
combine two existing patents, you would have a chance at getting a US
patent for it.

The US Patent Office confirms this by saying: "The right conferred by
the patent grant is, in the language of the statute and of the grant
itself, “the right to exclude others from making, using, offering for
sale, or selling” the invention in the United States or “importing”
the invention into the United States. What is granted is not the right
to make, use, offer for sale, sell or import, but the right to exclude
others from making, using, offering for sale, selling or importing the
invention."
http://www.uspto.gov/web/offices/pac/doc/general/index.html#whatpat

I suggest you read through the entire article listed above to fully
understand what a Patent is and to find out if your idea is
Patentable.

To answer another one of your questions (again from the same article):
"The patent is granted upon the new machine, manufacture, etc., as has
been said, and not upon the idea or suggestion of the new machine. A
complete description of the actual machine or other subject matter for
which a patent is sought is required."

The United States Patent and Trademark Office says that you can file a
for a patent without an attorney, but this is not generally
recommended.

According to this source (you can see a breakdown at the URL below),
it will cost you on average $5740 (more or less depending on the
complexity) to obtain a patent:
Patent Cost
http://www.patentsearcher.com/costs.htm

Another source more or less confirms this: "Based on the uncertainties
of the searching process, and the number of amendments and drawings
that may be required, one can typically expect to spend at least
$5,000.00 to $10000.00 in obtaining an issued United States Patent."
http://pw1.netcom.com/~patents2/What%20Does%20It%20Cost%20Patent.htm

If you are willing to try filing for a patent without a lawyer, I
recommend you read this article:
http://www.nolo.com/lawcenter/ency/article.cfm/objectID/021C9D66-3260-428F-83BBB68C2BE8A2DF/catID/00E99E7C-76B3-406F-AE703233C2157E4E

If you need to find a good patent laywer in your area, (many offer
free consultations), I recommend you find one here:
http://directory.google.com/Top/Society/Law/Services/Lawyers_and_Law_Firms/Intellectual_Property/North_America/United_States/

or the US patent office recommends you check your local yellow pages
for local patent laywers. (might be listed under intellectual
property).

I hope this is the type of answer you were looking for. If you need
any clarifications, please let me know and I will do my best to
further assist you.

tisme-ga


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