I ordered my last box from Costco (online), and it was much less expensive than my bank for checks with that duplicating page.
There's been a check deal on Fatwallet for over a year, and it still works (someone posted htat it worked on 1/25/2011):
"Get two boxes of checks from 4checks.com for $4.05 after offer code DE0378 when ordering online or by calling 1-866-923-0451.
Free shipping.
No processing fees.
Offer ends 12/31/10.
800 designs.
First time customers only.
Each box has four books.
Each book has 25 checks.
Be careful when ordering as they will sneak in the EZShield fraud protection. Need to select No twice."