Highly suggest making a separate F2P account linked to your main. You can do this via the RaF invite as stated or by creating separate b.net with same name and later merging them. Not only do you not have to pay for the account, but you can have it logged in at the same time as your P2P, which makes it easy to run yourself in dungeons, get AGM, win the fishing tourney, etc. Of course you also gain access to all the account wide stuff earned by your P2P.