Welcome to JavaRanch!
If you check
Sun's Java certification page, you will find that Sun's voucher for the
SCJA exam is currently $100. You purchase the voucher, and then schedule your exam at a
testing center. (See the "Exam Locations" link on the SCJA paged linked to above.) There should be no additional testing center fees. I would assume that San Jose has a fair number of options in terms of place and time.