10 bucks that goes a long way.
Personally, I researched Terraria for a few weeks to try and get a sense of what all the noise was about, and advise those curious to do the same. After watching numerous YouTube videos myself I decided to give it a try and found it to be the most worth while investment in gaming I've experienced in quite some time.
The sandbox quality to the game that lets you build to your hearts content coupled with the ARPG urge venture into the depths of your randomly generated world to find all those hidden items, baddies, and materials to craft a wealth of equipment with will have you playing enough to make you feel good about that purchase - I cannot stress that enough. With the speculation that more developers will notice this title and build on its premise is very appealing, while I hope that Terraria itself grows even more.
The content as it stands warrants the price - it's just a no brainer IMHO.