Every UO.com newsletter contains the following:
"We would also like to reiterate that the Origin store is the only guaranteed provider of codes for Ultima Online. The validity of a code purchased from a third-party seller (be it a friend, in-game acquaintance, or recommended site) cannot be guaranteed. Furthermore, any codes we find to have be fraudulently obtained will be disabled and an account that applies any of these codes will have that code removed from said account. This can result in the loss of gametime, character slots, expansion access, Sovereigns (and the items purchased with them), in-game items and more. Please be advised that we cannot assist with any issues stemming from codes purchased via non-Origin means; you will be required to contact the vendor from which you purchased the code for further assistance."
There is only one legitimate source of game time codes: the official
Origin store. Since no other sources can be discussed on Stratics and the question has been answered, this thread is closed.