Staples offers the Canon P23-DH V Printing Calculator, model no. 1904B001AA, for $19.99. Redeem this $10 mail-in rebate to drop the price to $9.99. Opt for in-store pickup to avoid the $9.95 shipping fee. That's the lowest price we could find by $13. It features a two-color ink roller printer, profit margin calculation, and clock. Rebate form expires January 14.