Rates really do shoot up for guaranteed services like 2nd day. $70 might be a little high but not by much accordign to my quick estimates. (20lbs from atlanta to houston would be over $46 by 2nd air, and I always expect to pay a bit extra for the guys's packing materials and time to get the box ready and shipped to you.)
I agree you should go with a standard service, preferaby the postal service rather that UPS, and you likely have it almost as quick.