In my experience if you delete an app you have paid for you have to try and re-buy it and type your password in but just before it would normally do the transac

In my experience if you delete an app you have paid for you have to try and re-buy it and type your password in but just before it would normally do the transaction it tells you that you already have the application and its a free download. I imagine the same thing might have happened if you had tried to buy the app you got on sale again.