The PTO website will give you the fee schedule for registering a trademark.
The real costs come from trying to protect the mark. It’s up to the owner of the trademark to protect it. The government isn’t going to help you do it.
A real life ® experience: our trademark became a federally registered mark yesterday, 12-21-99. The application and the fee ($245.00) were sent 10-27-98. 14 months.
My website was shut down once, 3 years back because some guy claimed copyright infrigment on his trademark logo. Took me some time to find out that logos aren’t copyrighted [they are trademarked] and they don’t have a trademark for their logo. sigh