I think you're better off upgrading the RAM yourself after purchase.
In addition to the oftentimes exhorbitant 'installation fee' you have to watch out for places taking out the original, Apple-provided chip and replacing in with no-name, lesser quality RAM. Never experienced it personally, but I've read posts here that have complained about the free RAM causing all sorts of issues (remember, OS X is rather picking about RAM quality now).
I'd say get the free printer and carrying case, but leave the RAM alone.