IPA: /ˌɪnɪkˈspɛnsɪvnəs/
KK: /ɪnɪkˈspɛnsɪvnəs/
The quality of not costing a lot of money; being affordable or cheap.
The inexpensiveness of the product made it popular among students.
Inexpensiveness → It is formed from "in-" (meaning not), "expensive" (from Latin "expensivus", meaning costly or requiring expenditure), and "-ness" (meaning the state or quality of). The word "inexpensiveness" refers to the quality of not being costly or being affordable.
Think of 'not' ('in-') being combined with 'costly' ('expensive') to remember that 'inexpensiveness' means the quality of being affordable.