It kinda depends if you just want the letter "Q", in which case most shops will either want a .SVG or "Vector" graphic (some will convert a picture you give them by e-mail or thumbdrive, but most will cha>>1175057
rge for that (we do, depending on the order, charge labour). Also keep in mind most times the vinyl needs to be cut out and adhered to a surface, and that also adds costs.
If you are content with a square/round shape with the letter printed in (as if you printed something on your own colour printer) but on adhesive vinyl, you can just give them a picture with high enough resolution. Best is to contact a
couple local shops and enquire what they need and will charge, but make sure you know what you want in advance before you contact them.
Hope this helped…
ps: added a vector letter Q from the stock Compaq logo library as an example