Extravagant shipping charge

UPS Stores are notorious for hefty shipping costs, even without their packaging. I once shipped a amp for service from Az. to Pa. from a Ups store. The shipping cost was about $103. The insurance brought the price up to $187. I think some people just forgo the insurance, for whatever reason, and take their chances. Which most of us know is pretty foolish, especially with very expensive equipment. And remember, even if insured and you have made a claim, you will not get  your shipping costs back no matter how expensive. 

" $150 shipping charge on a $150 item is ridiculous."

That statement is ridiculous. What one pays for an item has no relation to what it costs to pack, ship and insure. Weight, size, packing material, labor (if not done by the seller) and insurance decides the shipping price.

In these days of on-line calculators on USPS, UPS, FedEx, etc sites why buy anything shipping unknown?

This is an easy one.  Open up a FedEx or UPS account and let the seller use your account.  In fact, have the seller bring the item to a UPS store and have them package the item up and use your account to ship it.
If it comes damaged, you are responsible.

How much insurance was placed on the unit?  Did the seller use a new box, double box or anything special?  I ship items all the time, probably weekly.  A 60 pound item for $60 seems very cheap.  I recently shipped a SA-100 Counterpoint amp with $1500 to $2K insurance.  Cost was just under $75, 85 pound amp insured for $2500 was close to $150.  But again, depends on the insurance.  Have the seller send you a copy of the receipt.