First off, yes, $100 is LOT for a calculator. You may think, "Well, heck, I've got fingers and toes, and there FREE!" But, this thing will simply amaze you!
Yes, it is a bit bulky and big, but it's just got so much to pack into it! It also carries 4 AAA batteries and a watch-sized cell to hold memory when you turn it off/take the batteries out.
Yes, AAA batteries are expensive sometimes, but they will last you longer than you can imagine! I honestly think the batteries get old, not lose their charge first. That's not with just adding and stuff. I used mine in Geometry, and now Algebra 2, for graphing long complicated graphs, equations, even a bit of trig. This thing NEVER hangs while trying to figure something out for more than a second. You usually get what you need instantly, but every once in a while, for the tough stuff, it'll take a second.
Using some of the more complicated programs and features can be a bit daunting, but once you've done it a few times, it sticks in your head. I do suggest making a little note card of the things you'd like to remember how to do. After a break, it can be a little iffy on what you remember.
All in all, this is a VERY worthwhile investment for the high school, or college student. It may be a bit pricey in the beginning, but it's well worth it. As is the insurance, if it's avaliable near you. I've never broken one of these, and the class set at my high school has survived a few years of 8 hours of abuse a day. The only problem I've ever seen is the screen having a black spot, but that happens when someone takes a pair of scissors to the screen or something. They get dropped all the time (as does mine) and have faired amazingly!