Thats a pretty broad topic :)
Here are a few lists, not sure if they have pricing?<p>Maybe start with Google Web Store as most of them are web apps: <a href="https://chrome.google.com/" rel="nofollow">https://chrome.google.com/</a><p>This is a great list: <a href="http://startuptools.pbworks.com/" rel="nofollow">http://startuptools.pbworks.com/</a><p>And this Hacker News thread: <a href="http://news.ycombinator.com/item?id=1769910" rel="nofollow">http://news.ycombinator.com/item?id=1769910</a>