As far as I understand, once you've used your RAM to make a transfer you don't get it back.. I believe this is because RAM is used when you need to store your transaction on the blockchain. The EOS system has RAM available for purchase which fluctuates based on the Bancor Relay algorithm which is based on supply and demand. DAPPS obviously require lots of RAM because they will be required to store more information than users. You are also able to sell RAM for tokens and buy more when you need it.
Hope this helps, if anyone else has suggestions please inform us! I'm still getting into it.
hmmm...
well it doesn't seem like anything reset when waiting a few days...
and although I transfered some more EOS back into the account, figuring that might increase it's RAM and allow the rest of the transfers, that doesn't seem to have worked either. although there was enough to send ONE transaction.
do you know if staking tokens would increase the RAM?