An electric keyboard doesn't take up nearly the room that an acoustic piano does. There's always ebay, but Argos, for example, does some cheap and cheerful ones that would suffice until you decide whether or not you want to pursue the idea. One with full-size keys ideally.
My 'treat' is to buy some instant colour from the garden centre. Something that's already in flower in its pot and can be put in the garden after to have its rest and flower again when ready.