If you signed up for the subscription-based version of the Eaglemoss 1:900 scale U.S.S. Enterprise NCC-1701-D partwork build-up, you were supposed to receive four FREE gifts along the way. The first gift is this Collector’s Binder to safely store your issues.
Something I started doing recently was using double-sided tape to attach a 9 x 12″ clear vinyl envelope to the inside cover. This can easily hold the introduction foldouts and the full-scale photography sheet: