Should I buy promo CDs?

[extepan]

there is a shop in hong kong which sells ayumi japanese promo cd singles at 55 hong kong dollars (about 7 american dollars). there is basically no difference between the retail single, except that the barcode is covered and the disc itself has a word "sample" on it. do you think i should buy them? i mean i am not collecting the promo cds, i just want the songs...am i better off buying the retail version singles or these promo versions?