Good show, especially with that tough question of the predatory monetary practices common to free-to-play games, gacha systems, loot boxes, and EA's FIFA Ultimate Team schemes.
Let me tell you of the demons of gacha so you may never have to feel it for yourselves!
Dragalia Lost, the original mobile game from Nintendo and Cygames, does have a system where you are guaranteed to get the 5-star (the maximum) character from a given gacha banner. This system is present in Cygame's web-based gacha JRPG, Granblue Fantasy, and is colloquially referred to as a "sparking" system. Basically, you gain a special token for each gacha pull in Dragalia Lost. 300 of those tokens can be exchanged for any featured character in the current gacha banner.
The "best practice" in the gacha space is that each 10-pull is equivalent to 25-30 USD. In Dragalia Lost, they sell a premium currency pack of 1230 Diamantium at US$24.99. You need 1200 Diamantium for a 10-pull on a gacha banner. So, discounting the free gacha currency, free summoning tickets, the pity rate system, the maximum amount a player can spend in getting a desired 5-star character in Dragalia Lost is (napkin math) about 750 USD.
If you wanted to know about the hot gacha-anime-ARPG-BOTW of Genshin Impact, that has the "best practices" of limited time banners, bonuses for pulling 10 times at once, and a cost rate of $20-27 per a 10-pull (depending on if you buy the worse value or the "best value" pack of premium currency. Genshin has a "guarantee system" where at 90 pulls you get the coin flip (50/50 chance) of getting a banner's featured 5-star character or weapon and at 180 pulls you are guaranteed to get the banner's featured 5-star. So, the napkin math to that is a player could be spending a maximum of US$360-480 to get their waifu. Now the fucked thing is that there's a character perk system where getting extra copies of a character (up to six extra copies, meaning pulling the same character seven times to unlock all the perks) will grant them bonuses that are sometimes very powerful, depending on the character.
Finally, you have Fate/Grand Order which has a 0.6% of summoning the featured 5-star Servant per pull and no pity, sparking, or guarantee system whatsoever. As you can guess, there are salt/horror stories of people spending a grand or more and not getting the limited-time 5-star Servant.