Mwave offers the HL Components Battery Grip for Canon EOS 550D1 for $34.99 with free shipping. That's the lowest total price we could find by $13. It features a shutter release and can hold up to two LP-E8 battery packs simultaneously as well as six AA batteries.
Groupon offers a $60 Vistaprint Credit for $20. That's $40 off, $10 better than our mention from two weeks ago, which was $45 for $15, and the best credit offer currently available for Vistaprint. The voucher excludes shipping costs and sales tax and expires December 31.