I changed my address online, cost is $1, and at the end you get a coupon for $30 off $250 on every Sears Appliance and Electronics purchase (expires 10/31/2003 for me), plus 10% off one-way Penske moving truck rental AND 10% off Lowe's in the mail when you get the confirmation letter from the USPS. 
https://moversguide.usps.com/
Ya just don't get that sweet deal if you mail in the postcard. lol
Here are the deals I'm talking about (no these are not the actual coupons, you have to go through the change address process to get the "real" coupons):
SEARS
PENSKE
EDIT: see my latest post - rec'd 10% off Best Buy, 10% Home Depot, among others!
https://moversguide.usps.com/
Ya just don't get that sweet deal if you mail in the postcard. lol
Here are the deals I'm talking about (no these are not the actual coupons, you have to go through the change address process to get the "real" coupons):
SEARS
PENSKE
EDIT: see my latest post - rec'd 10% off Best Buy, 10% Home Depot, among others!