My first ISP, in March 1996.
Bought my first PC (Escom, remember them?) and a modem, was given a copy of the Demon software by a colleague who used them, and I was on the Internet that night. And thus was I back to MUDding.
Their email was STMP down and up, so when I wanted to use POP-only Pegasus mail, I had to write a gateway script (used FoxPro) to parse the email.
When the free ISP revolution arrived, I ended up switching to Tesco.net, until cable broadband arrived.