Beginning Oct. 1, 2014, you will no longer be able to purchase NX using the Ultimate Game Card and Pay By Cash payment options. If you still have any unredeemed UGC codes, be sure to use them by Sep. 30, 2014, the final date Ultimate Game Card codes and Pay By Cash will be accepted.
There will still be a number of payment options available for purchasing NX. Karma Koin is a digital currency available at retail stores and it can be used to purchase NX as well as other currencies and services with other companies. Other payment options include BilltoMobile, Credit Card and Paypal.
[Update 10/2/14 7:10 PM Pacific]
Karma Koin codes should now be redeemable again from Europe and Israel.