Selling, and drawing down, a "share" for a CSA
I'm a member and volunteer for a CSA (Community Supported Agriculture) group. Basically, we sell member "shares" in the CSA (at, say, $250) and then members then get to pick up products through the summer up to the value of their share.
The sequence of events is as follows:
1) Person buys member share, which then gives them the equivalent amount of "credit" to spend with us.
2) Person visits us, in person, at various points through the summer and chooses what they want to bring home for the week.
3) We weigh out their selection(s) and the value of what they picked up is taken off their share.
Do any of you have suggestions on the best way to handle this (unusual) use case with Commerce? Setting things up to sell the shares is easy, but we'd really like to be able to track their pick-ups as well so that our members can login to our website to see the remaining value of their shares.