Sophia Sophia, that Prime deal looks tempting and the white finish is very fresh looking. 61 keys gives you a wider range than the mini Casio with just 32 keys. However, the one drawback is the weight of it... it weighs nearly 4 kgs, whilst the mini Casio weighs just 1 kg, so you might find the weight on your lap a bit uncomfortable after a while, especially on a hot day. You could buy a stand for it, but beware of the ones that cross in the middle - I just could not get on with the one I had, because wherever I put my legs the cross part was right in the way - a cross I could not bear in the end! So, in my case I would probably get the smaller Casio, because it's so small and light that I can imagine sitting in the garden, or even on a beach somewhere, tinkering away beneath the sunshine.
Of course, there's another option - buy both! Keep one in the conservatory (if you have one) and use the other while out and about... spoil yourself!
"Don't let's ask for the moon, we have the stars." (Final line from Now,Voyager, 1942)