Is it standard policy for all auto repair shops to charge shop supply fee on all invoices?

I don’t know about that specifically, but I do know that it is standard policy for auto repair shops to screw you out of every dime they can.
I recommend everyone get a Haynes or Chiltons repair manual for their car, they’re $15-20 at any major auto parts store and it will pay for itself the first time you use it.

Some do …some don’t…it’s just a gimmick to make extra profit. I’ve heard of people calling the BBB and charging fraud if no actual supplies were used in their repairs. It’s like insurance where you spread the costs over many cutomers regardless of whether they use the service or need the items in the repairs….seems dishonest somehow. I try to avoid shops that charge this fee if possible. Most honest shops include costs of small items or normal shop needs like brake cleaner, shop towels, welding supplies, etc… into their profit figures and adjust their profit margins accordingly so it may be a wash either way…just never sat right with me….I always quoted jobs with everything needed to do repairs plus a margin for unexpected bolts, nuts, etc…that was removed from the bill if not needed. Some yahoo came up with the idea to make extra profit on the service dept and everyone jumped on the bandwagon….like 10.00 bandaids or 8.00 aspirins in hospitals.