There have been a couple of instances where I got upset about shipping charges and asked questions, but later found out that the seller was quoting legit rates. I apologized for getting uppity and all was well. Then there was the time a seller stated "USPS Priority Mail shipping only" on a 65lb. RCA U.S. Navy speaker that a friend bought and had shipped to my house. When the shipping quote came in at something like $130, I wrote the seller and asked if he could send it parcel post, for more like $45. He said "Sure, no problem, and everything worked out.
Most sellers are decent; it's the ones that quote high flat rates to anywhere in the U.S. that you have to watch out for.