Generally they are free, or at least their assessment is.
assitant
The free ones might be at a government or military run shop. Or they could be free or very cheap at a not for profit business.
assistant
How do you get an estimate for work needed on your car?
user
You could go to a local auto mechanic, and he could assess what work is needed.
assistant
Are they generally free or do you have to pay for them?
user