Thank you for putting this together.

30 years ago I self published a booklet on mortgage prepayment that I sold through the mail and made 50k in 2.5 years. Might have done better if Gumroad and KDP were around then.

I used adsense sites years ago and Amazon affiliate and made around $1k a month.

Your article has inspired me to start looking at ways to monetize my writing :)

Thank you!