Payment page: I need to give my customers an option to pay on my website (using credit card, paypal or maybe some other tools), but the problem is I do not sell any products for a fixed price, but services, whose price vary. So I need the customer to be able at the beginning of the payment process to input a price, that I am going to give him (via email or phone) and possibly also an order number, that I give him (now at step 5 some order number is automatically generated). So the PAYMENT PAGE should be very simple, just 2 windows for the customer to input price and an order nr, and a proceed button.. Can someone help? Thank you.