How did the first bitcoins get bought by anyone?
I understand how miners got them, but what did they do with them?
On messageboards like bitcointalk and chatrooms. People would use Paypal or other digital payment systems to send dollars. You could also trade in person through meetups and localbitcoins.com which still happens today.
in the first days of bitcoin there were no exchanges to buy bitcoin. if you didn't know someone who sells bitcoin you had to mine bitcoin (mining was less expensive in the first days of bitcoin).
Localbitcoins.com would allow people to meet up locally, and use cash or in person bank transfer. Also PayPal!