My new landlord said we need to pay for out mail keys?

Something is wrong with that picture. Your landlord needs to pay the $35 and she should have deducted that amount from the last tenants deposit. I am sure the law states that she is required to give you a key to all locks on the property. You could go ahead and pay for it yourself and then deduct it from your rent, just make sure to get a receipt to include with your money.