macrocephalopod

There we go. Now we're truly scraping the bottom of the barrel. PRICE CAN LOGICALLY NEITHER BE THE MIDPOINT NOR THE LAST TRADE, SO WHAT IS IT?!?

haha. why not mid? or if not mid just look at bid and offer. lots of options rarely trade, but the bids/offer still change.

WHAT IF THE MIDPOINT IS 0.10% AWAY FROM THE CENTER OF THE ARBITRAGE-FREE VOLATILITY SURFACE? HAHA, WHAT NOW?

well price of ordinary things is the price where you can buy, so just consider offer. If I wake up early tomorrow and milk at grocery is 10c higher then price has changed even though no one has bought it yet

What if I've got a coupon, what now, huh? And now what if the coupon expired, but I'm going to try using it anyway? Do we need a Bayesian framework to assess the likelihood of the coupon being accepted? Can I partly control my outcome by picking the nice old lady cashier?

My credit card gives me cash back on groceries, does that count?

But is the cash-back in exchange for selling your information? In which case, the grocery store paying 3% CC fees, but passing on part to you through the agency of your CC company's cash-back program, is actually giving you a 1% discount on milk in exchange for your information?

Spending any time working as a market maker ruins your brain because you realize that simple concepts like "price" don't have any meaning at the level you care about.