Need help finding a replacement tuning key

[timspong]

I have had this Martin Backpacker for years and one of the tuning keys broke. Does anyone know where I can get a replacement? I have been searching around and can't find anything cheap.

It isn't really worth spending a lot of money on this guitar and I don't really need it to match the rest of the tuning keys.

I cant figure out how to post a picture now that photobucket is no more. However it is a martin branded Rotomatic style machine head and it is on the bass side of the guitar.

thanks for your help.