I used to play Duel Links and shortly Master Duel after it came out. I don’t anymore but hopefully this will help.

If I was going back to the game, I’d go to look for budget deck lists and seeing what ranks up easily. Most of the community is on Discord and Reddit, as well as YouTube (yugitubers and alike) so I’d go and look there. (Not to mention Dkayed’s website, https://masterduelmeta.com and looking at the decks that topped, you’ll be surprised it’s sometimes not all meta stuff)

I’d also go look for some easy farming methods. These usually come in a form of a current event (IIRC in MD there are these “festivals” for each card type, such as Synchro Festival). These events are usually a very easy way to gain a lot of gems for not much playing.

It is what it is. TCG paper Yu-Gi-Oh is even more expensive than MD.

DL is arguably cheaper but it’s been a long time since I last played (2021).

EDIT: Oh and before I forget - there will always be Dueling Book as a free alternative. This is a manual simulator, not an automated one, and allows you to use any card you want with custom rules.

With pretty much all of these types of games there’ll be a cheap deck that’s really powerful. You can build that and then spam it to climb the ranks and get more resources to buy another deck. Back when I tried out Master Duel it was the Salad deck. It was pretty fun; I liked it a lot and I had it made on day 1. No idea what it would be currently.

However the games are absolutely designed in a way to entice you to spend money. They will always be slightly frustrating to play without doing that. It’s hard for me to recommend any of them if you’re not wanting to spend money.

Back in high school, some of my friends halfass doodled the equivalent Yu-Gi-Oh cards on index cards, as actual card games were banned. It was hilarious. And effective.