Hello Hassan,
You will get various prices from those who respond. It all ultimately depends on the place you take the car to for the sandblasting. Mind that they use a softer media blasting like nut shells, plastic pleets, etc. The reason is the sand is too abrasive and will warp and dent the heck out of the large flat areas and especially the hood, trunk, softtop case cover and doors as they are all made of aluminum. I would use extreme care when stripping these panels, the rest of the car is steel and should resist a harder media like mentioned above. The cost will vary so much, that's it's hard to pinpoint. Much like the paint jobs too.
I have always used a chemical stripper for all the cars except for the wagon-which was sandblasted-which ruined the roof so bad that I spent months correcting it. So dont fall into the same quagmire I did.
Best of luck with the rust and old paint stripping on your 230SL.
Walter
1967 230SL-diesel
1963 230SL-for sale