You can have both a trademark and a patent, though they won't be for exactly the same thing. A trademark can protect a creation's name, for example, and a patent can protect the actual creation itself.
Trademark protection is limited to the specific goods and services with which a mark is registered and geographic regions. Moreover, trademarks must maintain their distinctiveness, or protection can lapse, and certain marks, like generic terms, cannot be protected at all.
Assuming that a patent is available for the subject matter of your concept, that's the way to prevent others from pursuing the same product concept. A trademark, however, is useful—and often crucial—when you are building a brand for your product or service.
The cheapest way to get a trademark is to file a state trademark application, which is typically less expensive than a federal trademark application.
Under the “first to file” system, there exists no value in obtaining a Poor Man's Patent since it now only matters who filed for the patent first and not who came up with the idea first. Essentially, a Poor Man's Patent has about as much value today as the postage affixed to the envelope.
Likelihood of confusion is a common reason for refusal of a trademark application. The USPTO will review your application and compare your mark to any existing trademark applications or registered trademarks.
An individual can have a trademark without registering as in India, 'registration' of a trademark is not compulsory; both registered and unregistered trademarks can be protected against misuse. An "unregistered trademark" has no legal protections.
IndiaFilings provides tools and support for this search in the process of trademark registration India.