In 1996, Mom had been screwed over by phone reps for CompuServe's attempt at a true ISP stealing her credit card to order shit from Tiger Direct (told you this was a 1990s story) and was leery about anything online for years after that (and Tiger Direct was technically a mail-order catalog but it had a website).
But you're right that eBay and Amazon were two of the earliest trusted, in part because they were the two biggest/first to market. (And also, both proved themselves to be trustworthy, which was important in the age of fly-by-night e-tailers).
The same is true for PayPal.
By contrast I refuse to send my credit card number in an email or post it on a non-SSL site.
Guess which way I’ve only ever had my credit card number stolen?
This so much. I remember people's fear of filling in their Credit Card info online. And people who thought sharing Uber with a Stranger would be a no no.....
How time changes.