Over here in Australia we can get them from newsagents, as well as bottles of ink (eg Quink ink)
I learned to write 'joined up words' at school with a pen dipped in ink from a ceramic inkwell in a hole in my desk, as did many of us, I think. I was the ink monitor, mixing the ink powder and taking the ink round to classrooms, so I had permanent blue finger ends.
When I passed my 11+, my totally shocked* Mum took me to the newsagent to get a fountain pen, my first. She got shocked again at the price - 6/11d. As she had a cleaning job at 2 shillings and hour, the pen cost over three hours work - damn expensive.
* She had labeled all of us kids in various ways: John was practical, Steve and Dot were clever, and I was good with my hands. My passing any exam did not compute.....