Thanks, Dim. Now that I understand the mechanics, I can focus on strategy.
In terms of buying qqq options, one of the first things that comes to mind is price elasticity. I'm sure "inventory" is way down the list of forces that affect elasticity, but I have to ask: if a particular strike price has a large inventory (OI), does that make it harder to move the price, similar to the way a stock with a huge float does not move much in price?
You don't have to answer, I'm just kind of thinking out loud here.