Free Orders with Custom Pricing

Not sure if this is already a thing, but the ability for the client to create orders without upfront payment, then the internal team can assign a custom price to each order which then gets added to a monthly invoice that the client can pay in full.

All orders created in 1 month are invoiced as one, so my clients don't have to pay each and every time an order is made or keep topping up their account with credits.