Translators usually charge per 1000 words in the source text. There are no set fees. You could search for Polish to English translators on a site like ITI in the US and UK (different organisations but same initials) or the CIoL in UK and ask a sample what and how they charge. As an indication, 12 years ago I was charging £80 per 1000 words from Russian.
Carole Shaw, London UK
WOLFSBERGEN, BOSMAN: Holland
ZANDGRUNDT (plus variations), SANDGROUND: Warsaw, London and beyond
JACOBOVITCH/JACKSON: Staszow, Poland & London
KOSKOVITCH/KENTON: Staszow, Poland & London