From what I have heard, read, is that most embroidery shops collect a stock of alphabets i various styles. Helvetica, Brush script, Commercial script, IMPACT, Collegiate etc. You buy the digitized files (from say Dakota - guessing) and keep them as stock. So most people charge for the actual embroidery and garment on those stock items but not for digitizing since you paid for that in one lump package. Some I would guess probably add on an extra mark up and call it building in that digitizing fee. Now if they want a custom font, then you let them know you have a full digitizing fee. (This is only me assumption). I'm not well experienced in that area either and have only dealt with a hand full of embroiderers.