LoL skins. After a 3 year stint with a monthly subscription mmo long ago (pre-WoW), i vowed to stick to single fee (purchase price), or "free" games.
Friends sold me on LoL with its free client and champ pool. Was gifted a $10 rp card from someone and got 2 galio skins as he was my main that season. Felt sorta silly but wth it was a gift right? After switching mains and feeling bland i got some rp on sale and got a single skin (whatever was on sale, usually the older releases) for morg, garen and malph. Was upset with myself but thought a single $10 wasn't a big deal and being a noob, felt superior with my new skins.
Yada yada yada, fast forward a few seasons and role changes and bam. Not a single adc skin i didnt have. Would rotate support at times and clearly had to have every blitz, thresh, sona, janna, soraka skin as not to be some unclassy noob.
After about 5 seasons of being hard stuck in low tiers a finally quit. Spent an embarrassing amount when it was all said and done. Looked dope in my pulsefire ez tho...