Stable

[Raldo]

Krakka Roots generally cost less than 1k per root on the markets (on my server anyway), and the Magicked Stable Broom is 20k from an NPC vendor (and they're probably cheaper on the markets too). If you can't afford that, just keep playing the game. By the time you're trudging through all the lv50 main story quests, it feels like every quest throws ~5k at you.

The other chocobo foods are either to change the color of your chocobo, or to give it some kind of additional trait, neither of which are necessary. Though I suppose it is worth mentioning that it takes one Thavnarian Onion to boost your chocobo into every rank past 10, and those are relatively expensive, but you probably won't get there for a while.

Important note!
You may have been looking at the price of a "Magic Broom". That is just a minion and it cannot be used to clean a stable. You need a "Magicked Stable Broom". Magicked Stable Brooms are consumed every time you use them, so you will need several. Consider asking your FC if they'll keep several stocked in the FC chest or something.