Yes, WAMPUMS is a Scrabble word!

Letter values in Scrabble US: W 4, A 1, M 3, P 3, U 1, M 3, S 1.

Is it a valid word?

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

informal terms for money
small cylindrical beads made from polished shells and fashioned into strings or belts; used by certain Native American peoples as jewelry or currency