Setup an online marketplace using a virtual currency you control.
Many games offer players the ability to purchase items, points, or power-ups through an out-of-game system using "virtual" currency (e.g. Service Points or Goblin Points, etc). Traditionally, this would involve charcters contacting game staff in order to spend their virtual points for these power-ups. MyLARP, however, gives every campaign a virtual marketplace that works like a traditional e-commerce site. Now palyers can view their virtual currency balance and go shopping! You or someone you designate can create and configure items for purchase. Then, use the Virtual Store's order fulfillment system to keep track of whose orders have been fulfilled and which are still pending. MyLARP even keeps track of the currency expenditure, debiting players' balances as they make purchases or refunding points when an order is cancelled.
If your game does not use a virtual system like this, simply disable it in your campaign settings!