If this (screenshot of UI) is what people are paying $250/m for, and it's the best thing around then it looks like room for a simpler web based solution.
http://www.m1products.net/sms/manager/images/orderscreen.jpg
http://www.m1products.net/sms/manager/images/orderscreen.jpg
How many mechanics have email ? I think a large percentage.
How many people starting up new mechanic businesses are in their 30s or even 20s and reasonably net savvy ? I imagine quite a few.
Course these questions are best answered with some research and discussion with mechanics.