That's a 'big' question. One way to do this is to use a public array variable such as:
public var appParams:Array=new Array;
appParams=new Object; //--- User details
appParams=new Array; //--- Shopping cart (whatever!)
And so on.
There are some very 'clever' ways to do what your ask, but using Arrays generally reduces the amount of code required in an app.
Hi mtdevuk - I feel very rude since I have not revisited this post. I got this all working through singleton arrrays. The real deal was to get some understanding of the getInstance code - the persistance was the thing. Thanks for the update.