That's too old. I wouldn't even consider a car from the 90's especially with rust. Try to look for something newer. If you don't mind pulling an engine, there was the 2006 E 350. Those are in the $2-3k range, they had bad balance shafts and the labor to replace the balance shaft which requires engine removal is in the 5-7k so they're not worth it to fix. But the parts are only in the $400 range. Mercedes used lots of aluminum too so you'll see lots out there without rust.