Save yourself the time of going to a Post Office to purchase your stamps.  Purchase your cards and your stamps in one hit.

$1.50 worth of stamps can be used to post small letters and postcards, measuring up to 130 x 240 x 5 mm and weighing up to 250 g.  This includes most standard cards but excludes the Large Square ( 6 x 6" : 152 x 152mm ) cards.  You require $3.00 to mail a large letter measuring up to 260 x 360 x 20 mm and weighing less than 125 g.

Note.  You might not get the exact stamps as pictured, but you will receive $1.50 worth of stamps when you purchase this item.