We take Visa, MasterCard, American Express, Discover. If you are buying a monthly plan you can buy using AutoPay. AutoPay will allow you to order once and Grin Wireless will automatically renew your plan each month for you. If you are on the Standard plan or not on AutoPay you will need to order your renewal before the expiration of your active plan. If you have a monthly plan it gives you an expiration date and your plan is good through the end of that day. For example: you are on The 12 and you bought it on the 8th. Your expiration date is the 7th. If you do not renew before the expiration date your plan will be good until midnight Eastern on the 7th and then will expire. If you have cash balance you will be able to continue on cash balance until you renew or burn all your cash balance.