1 sat is 100 millionth of a Bitcoin. Sats are basically bitcoin. You might heard Bitcoin is slow and expensive to transact which in some scenarios is true, but this sats you received are transacting on the lightning netvork which is like a faster side layer next to a Bitcoin Blockchain. The cost of transaction are in dollars term almost nothing. 

Lightning netvork ⚡ is incredible sufficient for micropayments which are not possible with our traditional payment mechanism. With lightning you can transact a fraction of a centbin dollar terms. 

Zaps are like tips when we like or see value in someone's notes (post) they post we se value in that and nostr is probably the best way for V4V (value for value). 

I've made clean and easy (conversion calculator)[https://satoshi.si/converter.html] where you can check the price of sats you received or how much bitcoin you can get for some currency. Drag currencies up down or swipe them away if not needed. 

So in short, If some meme from someone makes you laughed out loud zap ⚡ the shit out of them with a sat or two. 

Or if somehow get caught in the Bitcoin conversation you can say "oh yes Bitcoin I pay my favourite blogger with Bitcoin"