I'm still sceptical about these few posts that claim they made it to lvl 15 without spending anything. Even if you got lucky and kept placing top 5's (I'm in a city with Fitz and Queen who I believe to be placed by ATA accounts so rip) it doesn't guarantee you the furniture and parts? Only cash, speed ups, pizza, roomie furnies ect. There is literally no way I see it doable and no one posted a guide for a reason, there isn't a way to do it lol. Even with spending "some" money it's hard. And no, it does not come to strategy. There is no way to strategise random drops. One will be inevitably money wall blocked by cushions, faucets and wheels needed to reach LR 15. If you wait, your upgrades are on hang, you lose time. Lvl 15 LR takes 3 days to upgrade.
Anyway, no one forced my hand, and I'm an adult, got cute crate items, but honestly, if you are prone to gambling addictions and similar issues just avoid these events all together, they are not healthy.