Thavnairian Onions are not easily obtainable, you cannot buy them from NPCs or anything and only three quests exist that gives you A Thavnairian Onion and the quests are not repeatable. Also, people charge an arm and a leg for them on the market board and you need 10 to max out your Chocobo. People charge 250,000 gil for A Thavnairian Onion, just one costs a quarter million gil and 10 are needed to cap your chocobo. Already checked all servers in my datacenter, you cannot get one for under a quarter million gil. I also looked at Thavnairian Onion seeds but don't bother, they are more expensive than the onions themselves, you might as well just buy the onions.

This needs to change, a lot of people cannot afford to spend 2.5 million gil on Thavnairian Onions. As an item that is heavily needed in the game, and hardly any ways to obtain them other than growing them—which requires a house or an FC with a house, it drives the prices to unaffordable levels.

The Thavnairian Onion requirements either need to be removed—or at least give us more ways to obtain them, or make them purchasable from an NPC. The way things are now, only those who can afford mansions can afford Thavnairian Onions.