 now at 3%, its lowest level in more than three years, much more closer than normal. It will cost you more at Costco, though, because the chain is raising membership fees for the first time in seven years. The price of a regular membership goes up by $5 September 1st. Higher-level tiers go up by $10. Delta shares struggling today. The airline's outlook fell short of estimates, even with super-strong summer travel demand.