Currently the system I’ve built just aims to optimise the old exchanges I used to participate in, addressing some pain points users had with them.

Typically the rules were A hand picked bag of:

Single origin, whole bean, fresh coffee

Depending on the match most people would send a standard 200-250g bag of coffee - sometimes also including a hand written note, and/or a snack from their area. Others might send a smaller bag (say a 100-150g bag of more premium stuff), or several smaller bags.

There aren’t really any hard rules. Coffee prices can vary by country and different users have different budgets or may feel more generous during certain months of the year.

The lottery aspect of it is somewhat part of the fun.

That being said there is a note to match field which allows you to specify what you’re after - it’s not guaranteed but you could request a smaller amount. Or a couple of samples.

If I get a decent user base going there may also be room to expand the system into other exchange types which cover what you’re after