I think the lower end of that range (250?). The OS they're releasing now will be good for another year and then who knows? It's quite possible that machine won't be supported this time next year. I'm not sure that's means for immediate panic, and who knows you might have two years until it happens, but at some point you might ask yourself if you want a machine that isn't getting software updates and the security that comes with them. Also consider that you can buy a new one for $1200, which used over the next 8 years would cost you $150/yr. At $300, two years of use of this machine will cost you the same; and it's old. I'd rather have the new one, but people can't always afford (have credit to buy) new. FWIW, if it makes sense or not, this straight line depreciation pricing is essentially what I've seen people asking.