I remember when my DH used to complain about the cost of fabric when I wanted to make a dress or blouse or pants. Finally instead of arguing I took him to the best store in town (where he bought me BD and Christmas presents) and made him look at the sales tags on some of the clothing there. I then led the shell shocked man out to the car and drove him home.
This was good for a couple of years.
Another way to get around it is to put a dress, shoes, fabric, into the closet and exclaim in wonder when he questions it "Why, no dear, it's not new. It's been in the closet for so long I've forgotten about it almost." Truthfully, it may have been put away yesterday, but without mentioning how long "so long" was you're not telling a lie.