I started playing with MidJourney a few months back. To say I am addicted to it, would be an understatement. It used to be free, but now they charge for it. If you're looking for a free version, I think Leonardo.ai is still free and it allows you up to 150 images per day.
The whole thing that I find super fascinating about MidJourney is the prompt equation. Being able to go into an imaginative forest and then come up with prompts that are then translated into beautiful visual representations.
Early adopters will tell you prompts are like Dollars. Great prompts are meant to be saved, savored, and then resued with your own spice mix.
If you go to MidJourney's main page, they have some amazing showcase
Go check it out. To use MidJourney, you will need to know how to use Discord. There are plenty of tutorials on YouTube that will teach you how to use Discord. You can then join the Discord channel for MidJourney and then let your imagination run wild.
The plus point here is that all the prompts can be seen in the channels. So if you like something, save it and use it.