4Game

Progetto 46 standard costs 45 euros iirc.

Think about three daily challenges for yourself, similarly to those in the game. My 3 challenges in the past 6 weeks were: 1) Do not eat fast food or mirelit food, 2) At most three espressos per day (or equivalent), 3) No snacking.

Each challenge gives you 50 eurocents, assemble a Google Spreadsheet to track them. 30 perfect days would net you 45 euros, but with some leeway (because you pick decent challenges to improve your life), you can do it in like 40-45 days.

You buy the Progetto 46 now, but you can play your first battle in it only after you have collected enough money with your dailies.

For a price of 45 euros, you get 90 dailies IRL, which you can use to improve certain aspects of your life, for example, health.

Obviously it can work with any other tank, or with any other microtransaction in any other video game. Or any kind of spending for some hobby of yours.

I am sharing this because I started this system in late January, and have just unlocked the Bourrasque. It was a decent IRL grind, but it acted as a superior motivation. I also added a weight loss objective, and thus I managed to lose 8 kgs already.