@Hengbok When you interact with the Gacha it will show u a list of items (3 in PSU, 3 or 5? in PSO2) you get to choose what is listed from the items inside the Gacha, it also shows u the price the spin will cost and how many items are left inside. Be careful those things are fun and addictive XD
As an example some people would place monomates worth 25? Meseta and 1-3 good items worth 500mil and each spin would cost 100mil.
I would be a bit more generous with the Rappy suit Gacha max it with yellow suits worth 2.1mil each and 2-3 higher end suits worth 7mil then set the spin at 2.5mil. That way people dont feel cheated out of their money and get something out of it regardless of how many times they spun . Its been a long time prices are not accurate XD
It was a nightmare for most due to the first example people would feel horrible afterwards. If done properly it can be quite fun tho.