Android

Hey, so what exactly do these android things do?
What do you need (heart + android itself?)
I've been told that all the hearts expire, so whats the difference between the cheap/expensive hearts

You need the android and the heart to actually 'summon' the android.
The heart has slots on it, which can be scrolled with every scroll, so android+heart combo will give stats (you can't use a heart without an android).
All hearts expire, save for some very rare ones that aren't out in GMS as far as I know, and the more expensive/higher crafting-level hearts have more slots, and the Deluxe androids can only use the better hearts.

Other than make faces and congratulating you on leveling/dying, they just stand there and look pretty.
For an android to work you do need a heart and the droid itself.
Android hearts can be scrolled with almost any scroll, so I assume the more expensive one have more slots.

Sounds a little ...underwhelming

Which are the ones that are perma? (I'm guessing not the deluxe one?)
What exactly is a princessoid?

All androids are perma.
No hearts currently available in GMS are perma.

And yeah, it's just a very bulky accessory with ~6 attack that you need to pay/work for every couple of weeks.

Other than make faces and congratulating you on leveling/dying, they just stand there and look pretty.
For an android to work you do need a heart and the droid itself.
Android hearts can be scrolled with almost any scroll, so I assume the more expensive one have more slots.

I believe the more expensive ones also last longer, although I'm not sure about that.

Android (F), Android (M) cannot use the more advanced hearts Garnet and Crystal, and they have less alternatives when it comes to hair and face styles compared to the Deluxe Android (F), Deluxe Android (M) and Princessoid. Princessoid also actualy speaks with a korean voice when you click it, log on or change channels.
All hearts expire after 2-3 weeks depending on which one it is, the non expiring kind is a rumor that is, to my knowledge, unconfirmed.