The tapes are free but the box is 10 bucks

I went out on my weekly garage sale crawl a couple weeks ago and found a guy selling a big box of old cassette tapes. Some of them were used blank tapes but most of them were all original store bought tapes featuring popular Rock bands of the 60's, 70's, 80's and 90's. From experience I recognize that some blank tapes (regardless of if they are used or not) can command good money in the after market. It's a matter of tape quality and if it's metal or not. I honestly don't know the secret to what makes a blank tape desirable but I'm always willing to take the risk. I also know that the original store bought tapes can bring in some money as well if you have enough of them and if rock or metal. Ok, I like this stuff and I'm willing to take it home with me for the right price. Here is how the negotiation went:

Me: How much are the tapes?

Seller: The tapes are free but the box is 10 bucks.

Me: Let me understand what you're saying... you're saying that I can go to my car and get some bags to dump these tapes into and I can take them home for free?

Seller: Yes but the price of the box just went down to 5 bucks.

Me: OK here's 5 bucks.

Flash forward to a couple hours later as I bring the box home. I tell my wife I bought a box of tapes and she laughs at me as I expected. Then she looks at the box and says it's nice and she wants us to keep it. It turns out the box is an old wooden beer crate for Moosehead Beer. It's actually a pretty sweet box now that I think about it!!