Once you get that trademark filed be aware that your information is of public record, which means, unfortunately, some will mine that resource & some of those folks will send you solicitations.
These solicitations often look very official, and "may use names that resemble the USPTO name, including, for example, one or more of the terms "United States," “U.S.,” "Trademark," "Patent," "Registration," "Office," or "Agency."
Some will even have documents that resemble actual government documents rather than what you'd expect a company to send and this is often done by "emphasizing official government data like the USPTO application serial number, the registration number, the International Class(es), filing dates, and other information that is publicly available from USPTO records."
Most of these are asking you for money. That's your major warning flag.
"All official correspondence will be from the “United States Patent and Trademark Office” in Alexandria, VA, and if by e-mail, specifically from the domain “@uspto.gov.”
If you did receive something that you're not too sure about go ahead and forward it to me - shannon at tmexpress dot com - and I can confirm if it's official or not.
Read more about what the USPTO has to say about this here.