There are a ton of apps now like "Music Downloader" that you can download free MP3s to that app. You can always download songs off the internet and import them into your iPhone through iTunes.
Mew seek is good. Requires a one time payment eventually but its only like 9 bucks. Plus it adds the songs right into your ipod instead of putting it in a folder to access on ur computer.
Yeah it sounds good but I just use the TransManager now instead of iTunes. Its very easy to use and can use on more then one computer which also helps.