When can I start buying items from the Argentum Bazaar?

Early in Xenoblade 2, when you first visit the Argentum Bazzar you aren't able to buy items from any of the shops. Whenever I try talking to a merchant, Rex thinks to himself:

I don't think I should be wasting time right now...

I've already been given the 100,000g payment from Chairman Bana, and was forced to give away 95,000g for story reasons. I'd like to use my remaining 5,000g to buy items.

How far do I need to play until I can buy items from the Argentum Bazzar?

Solution 1:

After buying a few things to complete the story quest Big Job Preparations, the game will instruct you to sleep in Lemour Inn.

After you’ve slept overnight, the shops will be unlocked.