All this talk of ziplocks makes me want to share my latest source.
My local Staples has over in the packing supplies area, 3 sizes of
small sturdy ziplocks,
2"x3" 3"x5" and 4"x6"
I like the sizes for stamps and logbooks, they also have a white area
on the bag for writing on.
Cost is low, small and Med are $1.98 for 100
and the larger were around $2.98 per 100

Good Hunting!
Nisha