Product price displays "per unit"?

Hello
In my store as you can see here
www.galeriadeartepedropena.com/tienda
the price is displayed in each product, but it also says "por unidad" ("per unit") and I dont want this, because I am selling paintings and its not necesary and it doesnt look good.
So how can I take that off?? is there an option or do I have to modify a specific file?

what?? I dont think you understood my quiestion. Sorry, let me explain again, I DONT want the "per unit"(por unidad) to show up in the page www.galeriadeartepedropena.com/tienda , I want only the price to show up without the extra "per unit" (or "por unidad" in spanish). Do you understand? I only want the price to show up, nothing to do with the cost per unit weight.
Please let me know how can I do this? how can I have only the price to show up and NOT specify that its per unit.

Ok,
so I can just set the translation as a blank and the "por unidad" would not show up. OK
But what about in english? I am going to have my site in english also and I would like the "per unit" not to show up either.
How to do this?