How big were the frames?
If I were to ship a 64cm frame road bike, the frame alone would need a box 47x30, and that's with no rear wheel or crankset. I'd have to ship the wheels separate. I just checked and even a 42x25x8" bike box is $69 at FedEx via ground Home Delivery. More if they come get it at your door. Keep in mind that size is a 21" road bike frame tightly packed.
I've got a 69cm Raleigh I'd like to list and sell too, but the box would be 35" tall and 52" long by 8" thick. FedEx says that'll be $136.11. USPS won't take it at all.
At those dimensions the bike is packed much like a new bike comes today, bars off, seat off, fork reversed, wheel along side the frame, and pedals off. It just makes it in two bike boxes joined to fit that bike.
What gets me is how others get the lower prices? What am I doing wrong?
I did buy one frameset on eBay which got shipped to me with just two sheets of cardboard cut to fit each side, all taped together but that frame had its forks and rear triangle squashed a bit. That was post marked at $18, and was a 62cm bare frame. I'd never risk shipping anything like that. The seller was lucky it made it here at all.