Look up "Overton Window". Basically, you drop hints about your intent to do something shocking, like "honey, there's this awesome ATFM for sale down the street for $8,000 and I'm buying it, and that's that!!!". Of course she will be furious, but you keep talking about it for several days. After things come to a boil, you shift down to your real intention... the $2100 T2 you saw on Craigs List! Your wife will be so relieved that you aren't going to spend $8,000, she'll probably help you carry the T2 into the house!