The general consensus among commenters is that there is no fee to file the TM30 form. However, it is important to file it within 24 hours of arriving at a new location to avoid potential fines. One commenter mentioned a fee of 100 baht if filed in person at a specific office.
Ana ************************
No fee
Larry *******
ORIGINAL POSTER
Filed within 24 hrs - 100 baht fee in person at Prachinburi office