I don?t have any suggestion to you where to go, but as you say you need small quantities, the best is for you to go to a computer printer, that has a good printer. If you go to an impresora, it will be really expensive for you as you will still need to pay for the negatives, the putting together on negatives ( different colors have different negatives ). This is a fixed cost that you cannot avoid no matter if you print 10 or 1000..
A digital printing ( possible on any paper ) has no negatives and therefor the cost is the same of 1 copy or 10.. What you do to be sure of the quality is you ask them to print 1 copy for you first.
I dont know what you are printing, but 1 8 by 11 cardboard printing in full color should not cost you more than around 20 pesos each. If it is half that size, then you can get 2 copies per page. That would include cutting as well.