Buy the guitar you want. Sneak it into the house and hide it. Play it only when the warden...I mean wife, is out, then hide it again. After about 6 months or so, bring it out and put it the stand with the rest. A Hercules multi-guitar stand works best for this. Keeps it from standing out in the crowd like a sore thumb. Pick it up and play it. When the warden (dammit, wife), comes and says...and you know the look...'is that a new guitar???'. Your reply and DO NOT HESITATE...practice this in the mirror...'this old thing, no, I've had it for years!' Then look away and keep playing! Oh, you could also say after that...'are those new shoes and did you get your hair done?...you look great and I love the shoes!'