A fire cape is the Fight Caves, which most accounts can do with the right gear and an hour of patience. An infernal cape is the Inferno, which is six hours, no saves, and the hardest thing a solo player can attempt in Old School. They look similar in a list and they are not remotely the same job.
Fourteen days of members access, bought in game with GP and redeemed on your account. It is on this page because it is the one thing every account needs and nobody wants to farm for, and it is the cheapest row here by a distance.
The capes are untradeable, so those are earned on your account rather than handed over. The twisted bow and the bond are tradeable and come by trade. The row says which, and the delivery selector is where you choose how the untradeable ones are handled.