Every time I go to a website and it says I must contact them for more information or a quote are just plain and simply trying to screw you over. No price online just tells me you want to squeeze as much cash out of your customer as possible.
There are no excuses. I know there can be many variables in quoting on anything. There is always a way to give a general price guide. Give us a general product cost be it by weight, volume or dimension. Give us a general hourly rate if required. Postage or delivery are usually more difficult.
Usually you can get some form of price for anything somewhere in the world except Australia.