Payments are due immediately upon win. I will combine items onto one invoice as I see you win more. eBay's new rule for Top Rated Sellers require we ship out items within 24 hours and can not hold items that have been paid for. If you pay full shipping and then want me to refund for the discount remember that eBay takes 10% on shipping once you've paid and does not refund me. I can not refund that fee to you but will do my best to refund excess. Thank you!