Money came into use because people became dependent on one another, importing what they needed and exporting the surplus.
mˈʌni kˈeɪm ˌɪntʊ jˈuːs bɪkˈʌz pˈiːpəl bɪkˌeɪm dᵻpˈɛndənt ˌɔn wˈʌn ɐnˈʌðɚ, ɪmpˈoːɹɾɪŋ wʌt ðeɪ nˈiːdᵻd ænd ɛkspˈoːɹɾɪŋ ðə sˈɜːplʌs.