Google One's benefits extend beyond storage space and customer service. Subscribers can save 20 percent on their next order from Google Express, up to $20. "Some qualified users" are eligible for an even larger discount of 25 percent, up to $25; Google doesn't explain what makes a qualified user, however.

Qualified users will be notified of the promotion either by an email, a notification in the Google One app, or on Google Express. Choosing to redeem the offer will add the promo code to your Google Express cart.

As Google Express continues to expand at an impressive pace, 20 to 25 percent off your order could mean savings on just about anything you could want. Not a bad perk, especially if you're on the $1.99-per-month Google One plan. Some brands and products are excluded from the promo, although Google doesn't say which. Coupon codes are good through the end of the year.