I swapped for environmental reasons but saved £ in doing so:
Swap to a double edge safety razor. I spent £10 on a razor and £4 on 100 blades. Should last me at least a year, much cheaper than £10 for 4 blades every 6 weeks or so that I used to buy and no plastic so double bonus!
Reusable San-pro.
Buy decent cleaning cloths (I have the thick yellow ones). Cut in half, use, wash and reuse (I used to use cheap sponges then chuck them).
Invest in some reusable cotton pads.
A tip I took from here - put any leftover veg in a tub (either in fridge or freezer) over the course of a week. Add anything on the turn once every week or so and turn it into soup.
The obvious ones which my friends never seemed to consider - dry washing on a line rather than a tumble drier.
Mend rather than replace if possible. Make rather than buy if you can (I've made draught excluders, door stop, cushions, dog bed, turned old clothes to rags etc).
Buy a roll or 2 of generic wrapping paper after Christmas when they are reduced (I pick up cards, gift tags, all sorts of bargains then). I have recyclable brown paper stamped with stars which Can be used for birthdays and Christmas and cheaper than buying sheets here and there.
If there's something you know you'll need, buy out of season. DH bought a great tent in November, reduced from £250 to £75. I bought wellies in April (down from £50 to £15) and a waterproof coat (£70 down to £30).
I buy a lot of Christmas stuff this way too.