The first, and most likely problem is that you were calling big businesses. Larger business will charge an expensive flat rate on top of what the plumber gets. This gets very costly, therefore I suggest you call a "small" business to fix your problem.
IF you were calling a small business, there is a lot to it. I am a carpenter planning to open my own business, and I'll be the first to tell you that there are so many costs to run a business that need to be tacked into a quote to keep the business going...think of it this way. Each plumber will have to, make you a quote, drive to your location (gas costs money), purchase materials, solve the problem, and also cover the cost of book keeping and marketing their business. On top of that, they do not get bennifits, a pention, workplace insurance (incase there is an accident), vacation pay or holiday pay.
You can laugh at how rediculous those things sound, but where I live in Canada they are manditory.
You did the right thing in getting multiple quotes. If all the quotes line up, then thats what it costs.
Building renovations deploma