[Banking]
1: Wait for game to go on sale (right now or was recently)
2: Buy new account.
3: Create bank alt characters and bank guild.
4: Use guild bank and mail to exchange items between accounts.
If you’re truly running out of space and you have filled all 240 potential bank slots (you can expand up to 8 panes) then maybe you should consider selling some of your materials. Yes, prices fluctuate but you can always get almost anything back later when you need it.