Technically buying stuff from charity garage sales and then selling it on eBay, but that was more offline work than online.
Tried flipping hippy clothes, then tried a copywriting agency a couple years. Barely made profit.
Then spent $3k on Facebook ads to build a "make money online" email list. Didn't make a single red penny of sales from that. 100% loss.
My first $1k purely online was creating patreon.com pages for Russian dancers that I know and keeping a cut.