That started 2008. House was paid off over 10 years. At peak those eBay resales amounted to about 5000€ annually, but mostly around 2000€ anually. That extra tax free money came a long way in paying of the loan.
Of course the government caught on to people doing that and limits the amount of private sales you can make at 2000€ a year, before having to declare it.
Luckily, by that time, my dad had gotten himself a decently paying job and didn't have to rely on that anymore, but if it wasn't for years of grinding eBay it would've probably taken twice as long.

Yeah that sounds very unlikely