You sound like my mother. When I say cheap, I mean not expensive, as in getting ripped off. If I was going to buy "cheap", I would be taking a trip to B&Q not putting a thread on here asking for a pointer.
As I said earlier, I`ve had them for 8 years and they`ve had some heavy use in that time, I think they just got weaker over a period of time and when I had to pull them out a bit further than usual, to clear a bay window, I heard a crunch and saw one of the legs with a large crack right the way through it.