I generally agree that it pays to buy the best you can afford if you want it to last, but there are exceptions. In my case it was accidental, sort of.
I was about to move house, and the toaster and the kettle both stopped working within two days of each other. Being in chaos at that time, I rushed into nearby Asda and bought both kettle and toaster for £4.99 each, thinking that I could look for something better after settling into my new home. Well, here I am, five and a half years later and still using them as they are both in perfect working order.
I now find myself wishing they would break down so that I could buy something nicer, but I am far too mean to replace them before necessary!