The quotes that you plan to use are much more likely to be protected by copyright than by trademark. The issue is therefore whether this use would constitute fair use.
Fair use is defined by 17 USC sec. 107, and generally includes comment and criticism, news reporting, education, and research. Whether a particular use constitutes fair use depends on the following four factors:
"(1) the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes;
(2) the nature of the copyrighted work;
(3) the amount and substantiality of the portion used in relation to the copy-righted work as a whole; and
(4) the effect of the use upon the potential market for or value of the copy-righted work." 17 USC sec. 107.
Applying these factors to your proposed use:
1) Your use is clearly commercial in nature. This factor will weigh heavily in the fair use analysis.
2) The copyrighted works were created for commercial sale by the copyright holder.
3) A quote is probably a small portion of the overall work in which it appears, but was probably selected for its significance within that work.
4) Although one might argue that the sale of your products might increase awareness of the copyrighted works, I believe that a court would find that your proposed use would have a negative impact on the ability of the copyright holder to profit from their works.
When you say that you are going to quote some famous poets, this leaves open the possibility that the qoutes may come not from copyrighted poems but also from other things the poets may have said, which may not be copyrighted.
Depending on the dates when the poets lived, it is possible that their works are now in the public domain. The duration of a copyright is set forth in 17 USC sec. 301-305, and is, on a very basic level, the life of the author plus 70 years.
You can perform a search on the US Copyright Office website to determine whether a copyright has been registered, and who owns the registered copyright. The website is http://www.copyright.gov/
Keep in mind that registration of a copyright is not a necessity for copyright protection, and is only required for court jurisdiction, statutory damages (but not actual damages), and attorney fees.
I encourage you to seek a license from the copyright owner of any work from which you intend to use a quote. In my experience, royalty rates are typically quite reasonable.
The following is not legal advice and should not be relied on to take or refrain from taking any action.
This question is often asked. The answer, unfortunately, is "it depends."
There are two bodies of law that need to be considered: copyright law and trademark law.
As for copyright law, the starting point when thinking through the question is the rule that short phrases are NOT copyrightable. See 37 C.F.R. § 202.1 at http://tinyurl.com/clr6bf and http://tinyurl.com/dzza5s . Indeed, in the context of news organizations reporting facts, courts have held that entire paragraphs are sometimes not copyrightable.
Courts have applied this rule quite often (e.g., to the phrases “Listen Up, It’s More Than Talk, It’s Feeling” / “You Got The Right One, Uh-Huh” / “Protecting The Earth From The Scum Of The Universe" / “You’ve got to stand for something or you’ll fall for anything” / “Eat Your Art Out, Chicago” / "Priority Message: Contents Require Immediate Attention"). In short, none of these phrases are copyrightable.
However, courts sometimes cite the rule that when a single line of a larger copyrighted work (such as a movie or poem) is appropriated by an alleged infringer, the test for copyright infringement is whether "the work is recognizable by an ordinary observer as having been taken from the copyrighted source." If so, then the court may find that copying that one particular sentence would infringe the copyright in the movie or poem. Though courts sometimes cite this "rule" when considering instances of alleged infringements of short phrases, it is very rarely -- if ever -- applied to dispose of a case (i.e., to hold the infringer monetarily liable for the alleged infringement).
Nonetheless, if a phrase has become so well known that it may be considered "the heart" of a copyrightable work -- e.g. "ET phone home" -- then the court will find a way to preclude anyone other than the copyright owner to exploit that phrase. Especially for commercial purposes. So ... as far as copyright goes, you're on safe ground as long as the short phrase is not the "heart of the work" and the phrase is only a minor portion of the work (you need to consider this second condition seriously when using quotes from poems).
As for trademark law concerns, many short phrases are used to brand goods or services. Before you slap a phrase on any widget and then offer it for sale, you need to ensure that the phrase you've selected is not already being used as a trademark. You also need to be aware that trademark law proscribes the sale of products that consumers falsely believe are being offered for sale by a particular person or company or are falsely associated with that person or company.
Before you begin to sell any products that exploit the work of others (and, yes, creating short phrases is work) you need to discuss the matter with an intellectual property attorney. While short phrases are often part of our rich public domain, some are not and are rightfully the property of others.