You're not spending thousands to earn $6 lol, you wouldn't be even paying for a website & hosting if that's the case,
It's all about the possible ROI & revenue, if you spend $10k on links & earn $1000 per month, that's $2K revenue in the first year & probably $10k in the second year ( as you'll need fewer links to maintain the ranking usually afterward),
Not to mention the actual value of the website as an asset that could be sold for at least $20K afterward, just do your research/estimations/math,
When it comes to how & what type of links you need to invest in, do your research, there are plenty of useful guides/posts shared on BHW,
Just stay away from the majority of the sellers who are selling cheap links promoted as 'high DA', 'High Quality', etc... They're complete trash,
If you believe that a high DA will get you good rankings, you're being fooled by one of the most shared misinformation to promote scamming services