In our next collaborative post, Shaelynn Farnsworth (@shfarnsworth) and I discuss how schools and districts can make the best technology purchasing decisions.  Recently I was talking to a Tech Director colleague that was in the middle of a purchasing battle with a principal. The principal had been approached by a well-known technology vendor wanting to sell the school some hardware and software to help students in literacy and math. The vendor was long on promises but short on delivery. The…