free postage or not?

As the title suggests Free postage or not? for me i have better custom by offering free postage i think it stands out as everyone likes something for free. i tried out 2 idetical products selling for the same price, one 1.20 free post and the other 1.00 20p postage and listed 10 items on each listing the one with free postage sold 5 the one with payment postage sold 1, so now even when i sell larger item i sell them with free postage.