tablets are FANTASTIC. I have had my tablet for close to 6 years now and it still works absolutely perfectly. I do a lot of work in traditional media as well (painting, pencils, etc), and I used a mouse before I had my tablet, but my tablet has been fundamental in my growing as an artist, especially in my digital art. they are a great investment, and Wacom makes them to last a while.
A forewarning - at first you may not be able to sketch directly into photoshop. For me, for a while, I would scan a sketch I did on paper and then ink it in photoshop on a new layer. This allowed me to get myself accustomed to using the tablet. Slowly I began sketching small things directly into photoshop and I practiced and practiced and practiced - and now, I just open up the canvas and begin sketching.