Price of copper tubing!

I used to work in a plumbing supply from early 70's to mid 80's and 3/4 x 10 ft. L was $8.50 a length. I went to Ace hardware and they had a length of 3/4 and the price tag said $5.50. I said not bad and brought it to the register and found out it was $5.50 a foot. Luckily i have a friend plumber that sold it to me a lot cheaper, don't remember how much but still cheaper than the store. He told me that China was buying it all up so that was part of the reason of the steep price increase