There are a lot of variables, but $700 for a running old Willys is pretty good.
Is it a CJ3B or a CJ5? I believe both had the Hurricane F-Head 134cid engine, both had the t90 transmission and the t18 transfer case. They also shared the Dana 25 & 27 front axles as well as the Dana 44 rear. The CJ5 may have had the dauntless V6 at this time as an option, but I am not sure.
The CJ3B has that flatfender Willys look and the CJ5 has the rounded styling and a bigger body.
Anyhow - $700 ain't bad. If it's working and not too rusty, I'd buy it.