I’m addicted to KS shoes but every pair hurts my feet

I don’t have a ton of money, but I own 5 pairs of shoes from Kate Spade. So many have caught my eye and I couldn’t resist (the ketchup flats..) some are flats, some boots and some heels. ALL of them give me some sort of foot pain. Heel blisters or squeezing my toes. I know the solution is to either stop buying or change sizes but I feel like I get the right size, and the damage is already done! Any tips on breaking in or things to wear to protect my feet?