Payment gateway for manual payments (Bank transf/deposits)

I am setting up the membership plugin. I though I could add payment gateways. I need to have a payment gateway that charges a fixed amount monthly and it's "paid" manually. I mean, our admin users would clear the payment each month. We receive payments via Bank transfers or deposits. We don't have a payment gateway that supports Bs (Venezuelan currency), so we need to do it manually. I would use the "Free membership" but the members would be confused and wouldn't know how much to pay monthly.