Window kits are great, but don't just buy the kits in the boxes. Go to a home improvement store, and buy it by the roll. The plastic is a lot thicker, just as transparent, and you'll save money (a LOT). I bought a couple kits, then went to the roll when things got tight. I wish I'd started with the roll! For tape, I use masking tape for most places, and duct tape on cinder block. Works like a charm. an additional benefit of using the roll of plastic is that it is strong enough to withstand removal and reuse. Which means you don't have to buy it every year, and you can put it over drafty doorways that aren't used very often.