Copied from my post at iLounge (because I am lazy)
I haven't paid for any apps yet, I don't mind paying for a quality app but I would like to know what I am getting first. Why no previews or free trials? It also seems that many free apps are as good or better than the paid ones.
My favs (all free)-
Shazam - hold the iphone up to any music source and it will identify the song
Zenbe - Allows you to create lists on your computer or iPhone and sync them. If you check off items they drop to the bottom of the list or you can delete them. I find it much easier to create lists on my computer but it is nice to be able to add things on my iphone. It was a little confusing figuring out what part of zenbe synced with the iphone (lists.zenbe.com) but now that I have it set up it's great.
iWant - There are several apps that use GPS and yelp to find businesses near you but I have had the best luck with iWant. You can adjust the distance in the settings.
Places - Same idea as iWant but I don't like it as much. It gives businesses within 1 mile then allows you to touch to expand your search distance.
HereiAm - Finds you location and allows you to email it to someone. If they have an iPhone or are on a computer they can click the link to see your location in google maps. Since you can email yourself it seems like a great way to mark your location instead of the paid 'remember where I parked' app.
Weatherbug - better than the included weather app.
InstaPaper - Mark articles on your computer hat you want to read at a later date and the are saved for you. Most articles are converted to be easily read on the iPhone.
Solfree - Decent little solitaire app, hey it's free.
Nuevasync - not an app but works great for syncing your google calender with th iphone calender