"Oni szukają tańszego łóżka."
Translation:They are looking for a cheaper bed.
It's 'cheaper' – one that costs less, than the not mentioned one, that is basis for comparison. Say there is this nice bed that costs 100€ you look at, and you consider sending the pics to your friends who are looking for a new bed, but someone who is with you, knows that their budget is only 70€ so they say „Oni szukają tańszego łóżka”, so you wouldn't bother, as „oni” will not buy it anyway. ;)
thank you, i know what cheaper means, i would like to see the translation of a cheap bed into polish language