Option greek letter explained

https://www.reddit.com/r/wallstreetbets/comments/k2o6i3/preheat_gme_tendies/gdvuptz/

20k for 400 x 10c at 0.50 for April 2021...

You need to learn delta, theta and gamma, those are the most important when trading options. Think of yourself as Keanu Reeves in Speed, every option you trade is the bus (your premium) you’re on if your bus drops below 55 mph (your strike) the closer you are to blowing up (0). The speed is delta, the acceleration is gamma, and theta is the friction between your tires and the other cars ahead that slow the bus down. The higher your delta (the speed) the more your option(s) is worth, thus your vehicle doesn’t blow up. The closer the stock price is to your strike the more it increases in worth via gamma (it accelerates the change of speed/delta). If your speed doesn’t hit 55 you never make any money so theta are the cars that get in your way or the friction of your tires constantly taking you away from your speed (delta). The more time you have until expiry the less theta matters, the converse is true the less time you have the more that theta eats at your profit.

I spent 20k back in May on 10c for 0.50/contract. At one point due to combination of theta and wide-bid ask spreads it went down to 0.33/contract. The closer it got to $10 the more it was worth, when it got to like 10.50 my option was worth about 3.68. But now that it’s way above my strike of $10 it’s worth way more