back in the mid to late 90s, I got a trial for compuserve that was a free 2 month trial. I liked it as as they provided dialup PPP access so was able to use it as full time internet access. It wasn't quite "2 months" of access though. It was 1500 hours of access (which in practice > 24*62).
However, their usage accounting software wasn't great. I had it setup to reconnect if the connection dropped, and they didn't do a great job seeing this, so they accused me of using 2-3k hours during those 2 months (should be impossible if always coming from the same #) and sent me a large bill (for the hours used over 1500). They eventually gave in when I showed them it was impossible and they could validate that the calls were coming from the same line due to the connection dropping and being simple reconnections.
Back in the same era, an enterprising young hacker of my acquaintance obtained unmetered access to another of those pay-by-the-hour dialup services by messing with window Z-order. The dialup service's GUI client had a free tech support area; billing stopped once you opened its window, and did not start again until you closed it. The rest of the system was all still there and running as usual - you just couldn't click on any of it while the support-area window was active.
So... this kid whipped up a little bit of code which let you force the topmost window to the back, and proceeded to spend impressive quantities of time online doing apparently nothing in the online service's free support area.
Heh there was some ad supported dial up Internet I found. you were supposed to download their browser and it'd dial in and work normal enough.
I noticed it created a windows dial up connection. When you launched the browser the login info worked on this. I could just dial their server and save the username and password and use any browser or game normally.
Was this NetZero? I kind of recall their CDs would do something similar, launch an Ad supported version of Netscape--but if you just copied the Dial-Up connection it made, you could recreate it without the need for the Browser.
Eventually NetZero forced you to use their own dialer to ensure you kept the ads running… but you could spy on the ppp connection by just opening the COM port of your modem in terminal and watching. The password was encrypted (xor?) but you could just copy and paste the value into a regular dialer lol
However, their usage accounting software wasn't great. I had it setup to reconnect if the connection dropped, and they didn't do a great job seeing this, so they accused me of using 2-3k hours during those 2 months (should be impossible if always coming from the same #) and sent me a large bill (for the hours used over 1500). They eventually gave in when I showed them it was impossible and they could validate that the calls were coming from the same line due to the connection dropping and being simple reconnections.