How to buy items above Max Mesos?

But it's only a slight inconvenience if the collateral is worth the amount you're paying (If it isn't, you're an idiot) because you don't actually lose anything on it.

"Slight inconvenience"? idk, for me, ending up without the item I wanted, and having to sell a bunch of big-ticket items, is more than a "slight" inconvenience. Maybe for someone who's merching anyway, it doesn't really matter.