I can't even tell you how many of these calculators that I have bought for my kids. One was stolen, one lost, one broke..........but the other day I was looking on Ebay and they had them relatively cheap for a graphing calculator~around $60. There was even one guy that was selling them from his store that were used at teaching conventions only one day. I wish I would have saved the site. I'm not even sure of the models that I have purchased in the past but I do know that some can be upgraded with new software. My daughter's teacher last year would have the kids upgrade as needed. OK~I'm sorry now I'm just babbling
