Micro Center retail stores offer a 4GB USB 2.0 Flash Drive or a 4GB Secure Digital High Capacity SDHC Card for free, in exchange for submitting a form about your email preferences. That's the best free, no-purchase-necessary offer we've seen from Micro Center. After you submit the completed form, the store will email a user-specific printable coupon. To redeem it, you must bring a valid ID. Coupon ends April 29.