Describing objects - Guessing Game - VIP

It is rather small and flat

and I've had mine for one year.

I use it every day 

and it is very useful for a lot of different purposes.

 It's a bad idea to have it in your room while you sleep.

There are a lot of different types.

Mine is blue and purple.

Most people have one.

You must charge it to use it.

It can be expensive, so not everyone can afford it.

When were you sure what I was talking about?

Are you even sure?

purpose - Sinn, Zweck, hier: Anlässe, Einsatzbereiche
to be able to afford something - sich etwas leisten können