Hi everyone I have a question about tuners. Someone locally has an SCT tuner for 1996-10 4.6 mustangs for sale for $100 but and it is "unlocked"

I don't know much about these tuners first off what does locked and unlocked mean?

Is $100 a good price for this tuner?

How much does a typical speed shop charge to tune your car with the tuner?

If I buy it I'm planning on using it on my 1997 GT to give it some more life and maybe change up the shift points on the auto transmission

 

where would you get your tunes from if you buy the tuner?

 

I would go to a local performance shop that specializes in mustangs