Prices of domains (usually; some registries do have premium concepts) are not stuck to their original registration but change over time.
x.org is registered with Network Solutions though and they never lowered their prices when domains actually got cheaper (=when the concept of registrars was introduced). So one-year renewal is still US$35 (http://www.networksolutions.com/domain-name-registration/pri...).
Nonetheless, in this case $35 should equally not be a problem either.
