Depending on the difficulty of the synth, I waiver around costs. Not gonna pay 30k for something at Skill 20, however, crafters spent a lot of time and money skilling up. They deserve some sort of compensation for their hard work. This doesn't mean that I won't accept a free synth... By Altana I love them, and usually tip them anyway.
If memory serves, I've never been impolite to anyone who's crafted something for me. I'm only at 68 and know how much of a *** it is. Besides, a little kindness goes a long way.^.^