Shocks /struts

I have a 1994 saville sts and I have a service comfort ride control error. I’m wondering how expensive it will be to have all 4 struts/shocks replaced…

Well, if those shocks & struts are original, then at about 16yrs old they might be due for replacement. But a ride control error does not mean that you have to replace all of your shocks & struts. Just take it to a good, local suspension shop and ask them to check out the system.