Bruce, I do understand that completely, however 150 is your average, base rate, it was the rate that was set for me by the store owner (I was terrified by this) the day I finished my apprenticeship (may 2011) and I simply have not altered it when I have moved shop as it was also their base entry level rate.
Anything detailed, or that I deem above my level that I want to try for a first time (the tiger or orchids and frogs for example) were done completely free of charge. and I refuse to take on anything that I feel is above me (portraits etc)

I know what you are saying about USD prices though, was looking at getting a tattoo by Scotty Munster and I was SHOCKED to see that he only charges $125 an hour! I could not fathom how an artist of such skill is charging so little, but I guess that is the difference between Canada and the US. I know when I was working in Australia for a few months over christmas I was only charging $80 an hour there (their shop rate). I think its really country specific.
I know the "tattoo school" here in edmonton has a base rate of $65 an hour for their students first tattoos, and $100 an hour thereafter. It really does depend on your locality for what you pay. Dont get me started on your drinks prices! lol