TRAVEL WATERCOLOR JOURNAL - CHEAP
Purchase a hard cover photo-album where photo pockets are bound with screws, not sewn in or with metal rings. (I purchased mine for $2 for size 5 1/2 x 6 1/2).
Remove plastic photo sheets by removing screws.
Tear (for nice deckled edge) or cut watercolor paper of your choice to approximately same size of sheets you removed, punch holes in the paper where the screws will go.
Refill little book with your watercolor paper and you now have an inexpensive little traveling watercolor journal.
You could do this with any size book (photo or scrapbook) that uses screws to bind the paper into the book.