Where can you buy Breezy Mission Letters?

The cost is Glimmer, not the event's own currency, so buying letters never eats into your Irisalis Petals. That matters because the same Legendary Journey event shop prices other stock in Petals: Glimmering Driftshadow, for example, costs two Irisalis Petals each. Check which currency a row asks for before you tap it.

The cap is five per week, and it covers both sides of the letter. You can buy five, and you can complete five. Buying a sixth is not possible, so there is no point stockpiling Glimmer for extra letters in one week. If you want the most out of them, spend your five every week rather than letting a week lapse.

Not settled: Five per week is the limit Breezy Mission Letters launched with. Whether the cap has been adjusted since then is not settled, so the counter in the shop is the figure to trust.