The word "heapest" is not a correct spelling in English. The correct spelling is "cheapest" /ˈtʃiːpɪst/. The "ch" sound is represented by the phonetic symbol /tʃ/ and the "e" in the middle is pronounced as a short vowel sound /ɛ/. This word is often used to refer to the lowest priced item or service, and it is important to spell it correctly to avoid confusion in written communication.