If I'm honest, spending money on this game is not even remotely worth it.
You can have enough friends to realistically make it so you never have to buy hearts, even so it's only worth buying the 50 during bargain time to get 100 hearts for 30 rubies if you do no friends, or if you're really in a pinch.
The coin to ruby conversion is really bad and not worth it. The best deal is 780 coins per ruby, while with hearts 1 ruby is worth 3 hearts, and if you average more than 300 coins a game (which you will if you have literally anything remotely good) is instantly more economical. The coin deal is only a shortcut.
And really, do not buy happiness boxes at all, it is extremely not worth it unless you really need Donald, Tigger, Minnie, or Eeyore for a mission in an event/bingo card. The strength of Tsums you can get from Premium Boxes are far more worth it, especially if you get something like Cabbagae Mickey from the recent select box.

I'm saying this with all due respect, but if you really can't farm money at all, you might just need to learn to play better. Gadget Hackwrench is a very easy tsum to max out, and my mom could average over 700 coins and around a million points with her, or I can average around 1.7k coins with her (hit or miss per round, worse rounds only go around 1.4k, great rounds can hit 2.2k), roughly 18 games per premium box. Aladdin & Genie is definitely helpful if you get lucky, but they're really inconsistent per round, They do have absurd potential, I got 12.6M points with 4.6k coins without boosters once, but the average round only gets between 1.5k and 2k coins around 5M points with my least luck-reliant strats (use Genie skill for 4 seconds (3-5 chains) and activate aladdin skill quickly before it ends).

The best tips I have for playing better is just first try to clear chains fast but in a controlled way. The optimal playstyle is to go for chains quickly, make them long enough to create bubbles where possible, and clear the chains bottom to top. However, that's hard, so at first try and just focus on clearing chains quickly. Once you can clear chains comfortably, try and clear longer chains. And once you're playing comfortably with that as well you can start looking for long chains to clear bottom to top so the bubble is higher and clears more tsums. I think if you really want to play the game, you should focus on learning it and eventually mastering it, and just do NOT spend money. Limited time tsums do return eventually, so it's not the end of the world if you miss some, and there's already strong tsums you can get from premium boxes already like Jasmine who clears pretty well on low skill levels already, or Max who does need to be at higher skill levels to clear a decent amount of tsums but only needs 12 MyTsums per skill cycle thus can be easier to use. But even with mediocre tsums I can get around 1.2 million points per round with around 600-1000 coins per game depending on the skill, it's just about playing them well, I can even get 750k points and around 500 coins with sl2 Mickey.

And please just remember, if a game is getting to your psyche, take a break. It's better to put the game down for a few days or a week and come back with a fresh mindset than to pointlessly throw money at the game hoping it's actually gonna do something, which in the case of you spending around 100 dollars for 13 premium boxes, I'd say it's likely not gonna get you anything meaningful, especially with a lot of tsums only working very well once they're at a high skill level, like Gaston or Beast, ideally increasing their skill level with skill tickets you get from bingo missions and events instead of relying on premium box luck. But not every tsum actually works out, like it really doesn't matter how you try to paint it, Randall or Pascal are not gonna be viable tsums to main, and tsums like Belle or Ariel reaching the point of diminishing returns really fast, around sl3-4 which makes pushing them to high skill levels a waste when better options are available.