One thing I really love about the ASP.NET community of developers (as well as the development community in general) is how we share things with each other for free. I love free stuff! Some of the best things in life are free; and the Internet is no different - especially now.
I recently added another website to my regularly used bookmarks - The Daily Plate. It's a free service that allows me to log my meals and my workouts with easy to use tools that tell me caloric intake, protein, sugars, carbs, etc, as well as how many calories I've burned. And based on my current weight, it can even tell me how calories I have left to eat if I want to lose 2 pounds this week. Very cool.
My brother, Sebastian, and I have both created personal family portals that our families use to maintain calendars, chores, blogs, photos, etc. Once our friends saw my brother's portal, they all asked how they could get one; so he reprogrammed it so others could sign-up to get one. It's called HouseholdPages.com. At first, he was going to do the free trial thing (like we used to do back in the day, which didn't work!); but I was able to convince him to do a completely free offering. After 6 months or so, he has 450+ families signed up. He has since upgraded the site with the ability to invite friends and extended family members with read-only access. The possibilities are endless!
If you're a developer that has built something based on a personal need of yours, I guarantee that someone else in the world needs the same service. But unless you a lot of due diligence, don't expect to start pulling in huge bucks right off the bat. People like me want FREE first; then if I can't live without it, I'll consider whatever premium services you have. Even without premium offerings, there are many creative ways to make money from your free offerings (including pay per click ads, sponsorship, etc.)
Here's some other free sites that I can't do without:
Don't forget about the million of blog sites out there - one's bound to have info you're interested in.