let me ask you this, would you really trust another entity holding thousands if not millions of your stake in something being completely free?
You do this right now. Your banks' infrastructure uses open and free encryption algorithms (and in most cases, implementations) and must do so in order to comply with regulation. So does your doctor (if you're in the US, at least). At no extra cost to you.
Additionally, mtgox is not and never has been a free service. They take a fairly large percentage on every transaction.
Nice straw man though.
Paying a recurring fee (purchasing tokens would be understandable, though as mentioned rsa can't really be trusted at this point) for two factor authentication and using a proprietary un-vetted password hashing mechanism means this service should not be trusted by anyone.
How about instead of using SMS as the second factor you use something that costs little-to-nothing, like, I don't know, an rsa private key signature? Or even better, why not an ecdsa signature from a bitcoin-related private key? I guess that just makes too much sense.