DiscountMags offers a
Popular Science Magazine 1-Year Subscription (12 issues) for $12. Coupon code "DEALNEWS" cuts it to $4.99
charges a penny more with auto-renewal.) That's tied with our mention from a week ago and the lowest price we could find by $2, although we saw it for $2 less in October.
Of note, you can purchase up to four years at this per-year rate.
Update: DiscountMags has since increased in price; however, Amazon still offers it for $5.