How To Find The Perfect Bed Topper

I've put this off as long as I could, but I can't anymore: I'm miserable. I'm getting crankier and crankier. I wake up every morning thinking 'what am I going to do, I can't go on like this'. The only way I'm going to be happy and satisfied is (and as much as I really don't want to I have to) I can't put it off any longer: I need to start 'sleeping around'!

I really need to get a new bed. I'm sleeping in a gully. Yes, I've turned the mattress around, but you can just do that so many times and the type I have now you can't flip. Over the past 2 years I've gone through 4 mattress toppers: feather, down, memory foam and nothing lasts. In as much as a decent bed is not in my budget right now and I can't see spending money on a junky one, I'm going for another topper. So here's my question:

Can anyone recommend one for me? One that's not going to shift under me whenever I lay down or make an indentation and stay like that?

Please, I'm a desperate woman! My back and legs are killing me, save me from 'sleeping around' and help me to find my own!