No such thing as pure curiosity, there is always a motivation behind curiosity.
..However, pure curiosity is a perfectly sufficient motivation.
Let me continue to be the contrarian on this.
"Why do you want to know how much I paid?"
"Well, I dunno. Just curious, that's all."
"How curious are you?"
"I dunno, why?"
"If I made a list of model numbers, would you be interested in getting on the internet and discovering for yourself how much I paid?"
"Hmmm, how many things would I have to look up?"
"Well, the list would probably contain about 25 items. It's more than that, but 25 would be a good start."
"25? Wow, that's a lot. Might take me a few hours."
"I'm not *that* curious."
"Oh, so you're saying that you're curious but not curious enough to do all that work, all that work that I had to do, not including all the research time, costly mistakes, and other costs and effort, to achieve what you see here in front of you?"
"Well, when you put it that way…"
"How would you answer me if I asked you the same thing?"
"I'd tell you to bugger off." [chuckle]
"Consider you've been told to bugger off." [more chuckles]