Yes, MAGAZINE is a Scrabble word!

Letter values in Scrabble US: M 3, A 1, G 2, A 1, Z 10, I 1, N 1, E 1.

Is it a valid word?

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

a periodic publication containing pictures and stories and articles of interest to those who purchase it or subscribe to it
product consisting of a paperback periodic publication as a physical object
a business firm that publishes magazines
a light-tight supply chamber holding the film and supplying it for exposure as required
a storehouse (as a compartment on a warship) where weapons and ammunition are stored
a metal frame or container holding cartridges; can be inserted into an automatic gun

Also: magazine publisher, powder store, powder magazine, cartridge holder, cartridge clip.