I try to get every last drop out of the toothpaste tube. It's surprising how much is left when the tube looks empty.
Marmite and Bovril jars are turned upside down to 'extract' every last drop and washing up liquid, bubble bath and shampoo have water added to prolong their useful life.
Seeds are saved from year to year and I haven't purchased any new this year. DH thought that the old broccoli and cauliflower seeds wouldn't germinate so he sowed the rest of the packets. We now have about one hundred seedlings! Whoops!