Yes, USANCES is a Scrabble word!

Letter values in Scrabble US: U 1, S 1, A 1, N 1, C 3, E 1, S 1.

Is it a valid word?

USANCES is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

the period of time permitted by commercial usage for the payment of a bill of exchange (especially a foreign bill of exchange)
(economics) the utilization of economic goods to satisfy needs or in manufacturing
accepted or habitual practice

Also: economic consumption, use of goods and services.