There are several things to keep in mind while boxing your saddle. The most obvious is weight but not everyone thinks of measurement. All carriers charge a premium for oversized boxes. Just going over the length by 1" can cost you an additional $20. I've shipped 45lb Western saddles all over the country for under $60 and many times under $50. If you paid $100 to ship a saddle, you didn't do it right. BTW, I've found that USPS was usually cheaper and faster then UPS ground. I've never wrapped a saddle in bubble wrap and never had a problem - but always ship it insured.
Check the USPS website and do a bunch of "what ifs" with different dimensions to see the difference in cost.