Fair enough. However, I have never mentiond the number $300 either. Maybe I didn't say it right. I should have said the cost can easily go above $100, which is ususally what I see. Most people in my area dive with steel tanks, LP85 and HP100 are very common for tech divers. I have seen bigger.
Sorry, I mis-remembered. You said 'hundreds of $$'.
My point is that unless you're dumping gas way too often, the amount of gas you use is the amount you pay for. That's the same whether you put it in 100's or 80's.