You do not have to be sponsored to attend a match, that is a requirement to become a member of the NCPS club. For most ranges in NorCal, you need to have some prerequisite experience to action pistol or taken an orientation to action pistol. If you would like to attend Sac Valley matches please refer to the link below to take the action pistol orientation. Once you have completed this, you will be able to shoot USPSA, IDPA, and even Steel Challenge.
actionpistol.org
Ron Sechler and Carlos Katalbas are great people to work with and enjoy growing the sport.
EDIT:
Just saw that you're located near Stockton. Please take a look at Linden Gun Range. The club that operates out of there is Linden Competitive Shooting Club and they hold matches and practice days. They are a premier club that hosts great classes and put on high-level matches.
www.lindencsc.com
Reach out to Mike Atwood @
[email protected] for more information.