Hi ZuZu! What a fantastic deal you found for a Tama-Go! *high five*
Take a look through this topic that binary started last year near the release of the 1st wave of Tama-Go's. I think the information provided there will give you a fairly solid understanding of how the Tama-Go works, its functions, design and overall "playability". There's also a general Tama-Go discussion that has been locked, but provides some great first-hand feedback from many TamaTalk users. Overall, I thought the Tama-Go was a great low maintenance Tamagotchi, something nice to play if you're busy with school, work, life, etc. I haven't really dabbled around in TamaTown that much so I can't say much about that - although I've heard TamaTown is down at the moment and has been for quite some time. The shell design is quite a bit larger than it's predecessors; it takes some getting used to. The additional Gotchi figures are a nice edition, but definitely not a requirement to play the Tama-Go. My one concern with the Wave 1 Tama-Go's was the removable plastic cover; it's prone to scratches and can create quite a glare over the screen if you have direct overhead light.
The Tama-Go is a great addition to any Tamagotchi collection. I think you've found a great deal, hope it works out for you!