Alpinord is right, the Riva's fall in the all around binding category (going up and coming down) like G3 Targas. A good overall binding, especially for a beginner, but a little on the less beefy side of things. Matches well with the T2 boot. The Big Bang has not been made by Rossi for a few years (pre-T series), but if they only have 10-15 days use on them, you got a pretty good deal. $75 doesn't buy much today.
If you get serious, upgrade to T1s, Rotta R8s or similar and wider skis as you improve. Better yet, get some skins and keep the Big Bangs for BC touring!