But you must have, or have had, access to warehouse prices. The general public has to buy retail usually, which always means paying the middle-men.
When you look up the "general rule" for CCA recommendations, it's usually given as 1 CCA per cube. So that means the old 202 would only need around 200CCA ! But with aircond that would go up so let's say 250CCA. So I'm sure that a 250 CCA battery would easily be only $140. But there's no way I'd consider putting in anything less than a 550CCA. Also remember that the CCA (Cold Cranking Amps) rating was created more for the freezing Euro climates. With the ratings given at some crazy low temp below zero. In Aust mostly, with our temps mostly well above 0 degrees, these batteries should perform better.
Personally, I think that like so many things in the last 15 years or so, where performance ratings are given, the figures are fiddled with. Or if not "fiddled with", they are used to mislead buyers into more confidence about the product which in many cases would not be as good as an earlier one of years ago. So a 1990's battery of average quality (eg Century or Marshall) rated at 500CCA and 100RC I'm pretty sure would outperform and outlast a battery of that same rating made today. Although I'd love to hear from and be proved wrong in that thinking by others with extended experience in the auto battery industry.