The fastest way to make money is to mine, a pretty generic response in my opinion, but there are ranked players on Prison that have shops that are able to get you money fast. In chat, people advertise their shops that say "60k 60k 60k" basically an inventory full of Lapis, Emeralds, and Diamonds will get you a minimum of 60k prison currency. There are also shops that buy "prison tokens" that you are able to acquire while mining. Prison shops buy tokens ranging from 20-25k per prison token. I hope this helped :)
Hi, Just to add onto this, if you don't mind spending irl money then you could buy some keys and get money or valuable items from them and sell them to get quite a lot of money. The main one is mining backpacks as they can sell for multiple 10s of millions.
Definitely just mine for a while and save up for spawners! Dont prestige to A1 until youve maxed out your plots spawner count :)
If you have an another account that you can set up chest shops with I could advise setting up a so called S1 shop where you can store the ores you mine. You can sell the ores, that you mine, to those chests for $1 just to store them and then sell the chests when the x2 booster is on. This way you can get double money from the ores that what you have mined in comparison to selling to mine signs.