Signing up for Costco this month should be on your to-do list. Find out three big reasons it pays to become a warehouse club member.

Earlier this week, a Costco shopper took to Reddit to voice frustration with the salespeople who approach customers inside warehouses to sell phones and phone plans. The customer complained that the workers have become overly pushy and disruptive with their sales pitches,

Costco's Q4 sales are impressive, but its P/E ratio signals overvaluation. See why COST stock faces challenges in the long run despite strong earnings.