How about selling Game Time capsules in Mog Station? An item that can extend subscription to sell to sell in-game. There will always be people who have in-game wealth, but have lesser means to support the game financially in real life (or have other priorities than the game's fee.)

It's a win-win. I, for one, is too busy to craft/gather and would much rather just enjoy the combat aspect of the game when I do play. As everyone knows, combat doesn't give you the Gil you need to progress lucratively. Some other person might enjoy the game for its craft and gathering and have played the market well, but is financially unstable in real life. Lets pair those together! I'll pay for a 30day subscription (via mog station and in-game item), sell you that 30day subscription for your Gil. Makes everyone happy, no?

Before you say it's P2W (pay 2 win), understand the logic that not everyone is able to fork out $15 a month easily. Or would rather not to, when they themselves have amassed a fortune playing the in-game economics. SE doesn't lose out on cash, as someone will pay for the $15 for someone else. Also, a limit on how many you can purchase in 1 month, and how many times the item can be resold (so nobody is hoarding them and re-selling for higher price.)

It'll be a player based economy (price will eventually settle out to what the consensus agrees on.) It eliminates RMT (for most part) as it'll be a legit sale.

TL;DR: I have IRL money, I buy in-game item that extends subscription, I sell it to you for Gil. We're both happy.

What do you guys think?