Having just read 5 Ways the Internet Saves Me Money, I decided to do my own list since mine would be very different from hers. Hers predominantly focused on shopping, either online or acquiring vouchers for use in real life. I'll not be talking about shopping at all (though I might mention something about selling) :-)
By doing just one of these things, you can save some money. By doing all of them, your savings really start to add up.
Five Ways the Internet Saves You Money
1) Reading News Online - In the past, I have bought either newspapers or magazines for my news. Daily newspapers were a staple of my house when growing up but since university I haven't regularly bought a newspaper. In the past, I also used to buy technical magazines (computing, photography, woodwork) but now I find that there are many more articles online and you just have to search for the quality ones. Also, especially in computing, the news in the magazines is about 2 months late compared to reading it on the web.
2) Online Banking - I had a meeting with my bank the other day and he tried to explain why their mortgages were at a higher rate than the online banks (a subject of another post). Predominantly it came down to the fact that they had branches and the other bank didn't. By using the internet themselves, the bank saves money and therefore passes those savings on to you. You'd also be using the internet in that arrangement too.
3) Keeping up with Friends and Family - Using email, instant messaging, VOIP phones and other forms of communication online, you'll save on postage, phone calls and all those other forms of communication which cost money.
4) Not Buying Books - Think of a hobby you do and think how much money you have spent on books for it. Unless you started the hobby in recent years, you've probably spent a fair bit. Now, try searching for information on that hobby on the internet. I'm sure you already have and I'm sure you found a lot of information. In some cases, enough that you wouldn't have needed to buy those books in the first place.
5) Selling Your Stuff Online - Whilst this seems a little bit of a cheat, selling stuff really can save you money (as well as gain some too). Just one example is the charges you have for throwing things away; save by selling stuff instead. Not to mention the fact that you'll also be getting money in return for those things.
Before I finish, I'd just like to say that using the internet can be a bit of a compromise. I use it a lot, therefore, I want it to be fast. I pay for a medium internet plan with my cable company so whilst I do pay more than I could for a lower end plan the savings via all these other avenues trade off what I pay extra.
I decided to focus on just five ways the internet can save you money and I will write a follow-up post with more ideas later on. Let me know in the comments any other ways the internet can save you money too.