4th gear's gone

man I'm so pissed...for awhile now 4th gear has been giving me a some trouble with popping out of gear while driving...and sometimes popping right out as soon as I let off the clutch...

well tonight on the way home I was accelerating to merge and it kept throwing 4th back at me...now I can't get it to stay in 4th gear period...even if I EASE into it.

I don't feel like dealin w/ tranny crap.

if it's just a synchro how much do you think it would be...it's the only gear w/ any sort of problem at all.