I recently attended a workshop to learn how to use the TI Nspire in the algebra 2 classroom. There are so many fantastic exploratory activities that can be done with students using this device. Our school district currently does not feel comfortable requiring students to purchase this or any other graphing calculator. Do your school districts require students to have graphing calculators. If so, which one do you require?
Our district provides a graphing calculator to students in algebra 2, trig, AP stats, and AP Calc. Each math teacher also has a class set of graphing calculators. We have a mix of TI-83's and TI-84's. We purchased 30 TI-Nspire's and 30 TI-Nspire's with the CAS for next school year. I'm going to one of the TI Nspire conferences in July... I can't wait! I already got my color TI-Nspire! It's awesome!
The color ones are particularly cool! Using a cas calculator in the classroom is changing my approach to teaching math altogether. If a handheld device can solve even the most complicated equation in one step, I do not feel the need to spend 80 percent of my teaching time on long pencil and paper methods of hand solving. I can teach my students how to do some simple problems by hand, then move into some of the more interesting aspects of math. I find that students are more interested in estimating and modeling than they are in calculating, so I get more buy-in from them too.
My suggestion may raise more questions than answers, but have you considered offering virtual calculators to use? I can't foresee how many available computers you have or what students have them at home, but I've reviewed the Microsoft Mathematics (calculator) application, and it runs about as nice as a TI-89. Not sure how it would work as a virtual poll or clicker, but it seems to do a fine job for Algebra 2 topics.