I shred my receipts... no evidence! But seriously, I don't buy nearly as much as I did when I first started quilting. And I wouldn't count rulers and other tools as part of the 'spending' money. Those are tools you will use again and again.
Back when my DH and I both had good jobs with benefits, I used to say I would only buy as much as would fit in my briefcase to take home at night. But now DH is on disability and I have a job with no benefits, no insurance, etc., so I am VERY FRUGAL with my purchases.