Purchase Karma 0.1.3b
Works with Karmabank and Marketplace plugins.
I would consider if and how you are goign to use this, you don't want to destroy the incentive to earn karma (set price a appropriately).
On the other hand it can be used to make up a sort fall in Karma, if a user has earned some karma, but not quite enough for that product.
This is a one way transaction as there is no exchange mechanism.
Even if you set a Karma price, a Spend Karma button will not show up as it is a bit ridiculous to buy Karma with Karma.