My wife has gotten me "pick your own" gifts in the form of gift cards several times by cutting out a cardboard/posterboard partial size version of the item she intends for me to buy, then including a gift card with it for a sufficient amount, and wrap that in a box about the right size for what it's supposed to be. Kinda like she's earmarking the funds for the TYPE of gift, but wants to give me the latitude to pick the exact one I want.

Only reason it came to mind is that she did that 2yrs ago for a pair of boots, same context as the OP.