TM question please help me!

[oberheimer]

Im going to start a music, movie site with a forum and a trading place for cd´s dvd´s vcd´s. Im also going to help new groups to sell demotapes. Do you think i should regg the TM aswell. It´s a one word .com 4 letters. There has been a TM on that word, but it was for books. it´s now dead.
How much does it costs to regg and do a pay a yearly fee for the TM