When something is expensive in English, we say it costs an arm and a leg. In Spanish it will cost you an eye "from the face" . I'm not sure where else an eye would come from, but hey, we're not here to criticize.
"Cuesta" is the verb costar, meaning to cost. Aside from costing you money or an arm and leg (or an eye) costar has another use.
If you say "me cuesta" it can mean that something is hard for you. Let's look at it in context:
A: Hola, ¿cómo estás?
B: Muy bien, ¿y tu?
A: ¡Que sorpresa! ¿Hablas español?
B: Si, hablo mucho, pero todavía estoy aprendiendo.
A: ¿Te cuesta?
B: Si, a veces me cuesta mucho, pero vale la pena.
Let's take a quick look our key phrases...
Is it hard for you?
Me cuesta mucho.
It's really hard for me.
Ya! That's it. After I heard this the first time, I started hearing it everywhere. This is something you'll want to have in your Spanish toolbox.
¡Hasta la próxima!