Discounts come from several areas:
For SUN, she hold
Java Certification Day every Decemember. If you join, you can have 30% off discount on the vouchers.
For Oracle, Oracle Univerisity hold Summer OCP courses for University Students. You need to pay HKD $7311 for the whole courses, includes 40 hours lectures, ILT materials, and 4 exam vouchers. Since Oracle enforces a course requirement for OCP, this is a good idea to get OCP.
For IBM, she has given out promotion last year. If you paid USD $10 for each ICE
test, and if you pass, IBM sent you a free voucher to take the real exam.
SUN and Oracle also give out beta exams. For SUN, all beta exams are free of charge. For Oracle, each beta exam costs USD $50.
Hope this help.
Nick
SCJP 1.2, OCP 9i DBA, SCWCD 1.3, SCJP 1.4 (SAI), SCJD 1.4, SCWCD 1.4 (Beta), ICED (IBM 287, IBM 484, IBM 486), SCMAD 1.0 (Beta), SCBCD 1.3, ICSD (IBM 288), ICDBA (IBM 700, IBM 701), SCDJWS, ICSD (IBM 348), OCP 10g DBA (Beta), SCJP 5.0 (Beta), SCJA 1.0 (Beta), MCP(70-270), SCBCD 5.0 (Beta), SCJP 6.0, SCEA for JEE5 (in progress)