Tao Mix is a free app ($2 to unlock all the features) that let’s you build your own nature soundscape. I have enjoyed playing with the free version and might end up getting the upgrade.
You can select up to 3 sounds in the free version and each category has one or two you can select from. (E.g. You can pick heavy rain, but medium and light are locked.)
Give it a try.
You can currently get Acorn 4, a great image editing program for Macs for $15! The sale is limited-time, so don’t blame me if it is back up to $50 when you check.
I’m constantly bouncing between Acorn and Pixelmator, which are both much less expensive (and smaller applications) than Photoshop, and have a much more friendly UI than Gimp.
A puzzle game with M.C. Escher inspired geometry, $4 in the app store