1) Never try to save money for a large purchase/project. The moment you get anywhere near your goal, something big and ugly will break in your house and you'll have to use your savings to pay for repair/replacement.
2) Repairing screens is easy - and a hellova lot cheaper than buying new ones.
3) Nothing is more cost-saving than a good "programmable" thermostat.
4) You can never have too much duct tape, superglue, rubberbands, or Lysol.
5) Enjoy your home - be happy. The office is ok, but home is sanctuary!