caching GET request results

I'm sure there's some info out there about how to cache the results of especially GET calls.
I read somewhere (but can't find it now) something about configuring "json/application" to be cacheable.
I'm NOT using boost etc. "just" memcache and authcache.

We have calls such as a GET to:

/anontestnode2/entity_commerce_product?parameters%5Btype%5D=postal_costs&parameters%5Bstatus%5D=1ers%5Bstatus%5D=1

Going to the DB is proving too expense - customers are seeing empty results

Thanks for all pointers