HTC US is doing promotion for all customers who bought and register a New HTC One before 31 July shall receive US$25 credit to their Play Store account.
However, it appears the following phones are able to register the same promo, but not sure they are going to send you the credits or not.
hTC Butterfly
hTC One X
hTC One S SE
hTC Desire 600
hTC Incredible
Saw this promo a while back, but from my understanding, it needs to be a US handset registered on HTC USA