1. Richard Sperry near routes 32 and 26 in Eldersburg.
2. Dent Wizard in Rockville.
The price was reasonable. They are located off Randolph Road, just east of 355 on the other side of the railroad tracks (adjacent to Staples).
They do not take appointments - its a walk-in service. If you go during the week (early lunch hour) you may be the only one there - if you go on the weekend you will need to wait longer.