Stamps
are available in post offices (Correos) which are usually open from
8:30 am - 2:30 pm, Monday-Friday and usually Saturday mornings, although
some are open uninterruptedly from 8:30 am to 8:30 pm. The cost of the
postage to the US of a regular postcard or letter up to 20 grams is
0.75 Euros. Stamps can also be purchased at tobacco shops (estancos).