WDC Dragon Vale

I am just checking I have understood this correctly - so if you purchase this for 100k GP's, any of the tasks you do, you double the XP?

So say you get 250XP for a product review you actually get 500k GP

You check in for 1 GP, you get 2 GP?

Have I understood that?

Is there a limit on how many times you can use it or how long you can us it or how many dragons you can use it for?

Thanks!