I don't know if this has been discussed before but I'll throw it out there anyway...
I used a local embroidery service that I paid a one-time setup/proofing fee of $125 to get my photo logo digitized for their stitch machines. I then took over a whole box of my own clothes, especially those I wouldn't normally wear (like those safari-type shirts that I seem to get as gifts) and have them embroidered for only $7 a piece.
Assuming that you wear clothes when you shoot (either during a job or just shooting), why not promote your business without even trying? I think it makes one look serious about the biz and keeps people from asking why you are shooting what you are shooting.
I hope you can use this idea.