Do you have a student that needs a good calculator but doesn't need a graphing calculator? My favorite model is the TI-30xiis. I recommend this calculator to all my middle school students because it's simple enough for basic use but offers the advanced features that students will begin using in pre-algebra classes. The TI-30xiis is also good for the future transition to a TI-84 graphing calculator because the key entry is similiar.
While this calculator is normally priced approximetly $14, back to school sales always see the model's price take a dive in August. Thanks to price matching and mail-in rebates, you can get the TI-30xiis for under $5 at Staples.
Staples has the TI-30xiis on sale for $10.99 after a rebate. The Target flier shows the TI-30xiis for $9. Staples has their 110% price match gaurantee so if you bring the Target ad to Staples, you will be able to purchase the calculator for $8.40. It's gets even better because you will still get the Staples mail-in rebate for $4. After the price matching and rebate, the calculator will cost you $4.40.