Staples has 10-Reams 500-Sheet Hammermill Copy Plus White Paper (8.5"x11") on sale for $34.99. At checkout, apply promo code 57236 to get 25% back in rewards ($8.75). I believe you must be a Staples Rewards member for this deal ( free to join ). Shipping is free.
Also see:
- 10-Reams 500-Sheet Staples Multiuse Copy Paper (8.5"x11′) $29.99 + $7.50 back in rewards (w/ promo code above)