Purchase Jim Schrager's book "Buying,Driving and Enjoying the Porsche 356". Driver 3/4 40K and up. #2 restored 75K and up Best for driving is the newest C model. Many prefer the lines of series A cars but they are a lot more expensive. Go to Bringatrailer and search for Porsche 356 for recent sales. By Excellence Magazine's most recent guide for prices. Or go to Hagerty.com Prices for coupes about 1/2 of Cabs maybe a little more. Condition of body is the most important thing. You can rebuild engine and transmission for less than redoing body. Because of the big price run up in the last 10 years lots of 356s have been restored by shops who don't know 356s and are IMHO "Lipstick on a Pig" cars. Be careful.
https://porsche356registry.org/article/164