I'm coming to this thread a bit late, but feel there's a need to clarify what Jim wrote, speaking from the trademark side of the fence.
A trademark is an identifying name, logo or other device used to show that the goods or services carrying that mark come from a common source; it shouldn't really be thought of as a name you give to a product. While it's possible to use a mark that way, it's pretty risky and trademark attorneys regularly advise against it. The risk is that, if the product doesn't yet have its own generic name, then the public could easily start using the "trademark" name as the generic term for for the new product. Iconic examples of trademarks that lost their trademark status by becoming "generic" this way are "aspirin", "thermos", and "elevator". TM attorneys frequently suggest their clients use marks as "adjectives" only, as a way to keep them from stumbling into problems.
Also, saying that someone doesn't need a trademark to sell an item, while true, could be misinterpreted. Many people don't realize that just by using a name or logo as a trademark in selling their goods or services, they are establishing trademark rights. They do not need to register the name or logo to have trademark rights in it, although registration helps in enforcing those rights. (And they could also possibly be infringing, if there's a likelihood of their mark being confused with a similar mark owned by a senior user.)
Finally, venturing with some trepidation over to the patent side of the fence, it seems to me it may be worth also clarifying for the OP that while he does not "need" to patent his device to sell it, if the device does meet the criteria of being "novel, useful, non-obvious," and anything else I may have missed that goes into patentability, by selling it or putting it on public display he could lose the chance of ever patenting it in many foreign countries and will start a one-year deadline running for applying for any U.S. patent on it. The OP would do well to read up a bit on patents to see if his new product, or any aspects of it, might be eligible for patent protection. Searching "patentability" in this forum may pull up some helpful background information. The PTO website at http://www.uspto.gov/patents/resources/general_info_concerning_patents.jsp
also has introductory information. And Nolo press has a book on Patent for Beginners which could be bought or even found at many local libraries: http://www.nolo.com/products/nolos-patents-for-beginners-QPAT.html