National Geographic Store has an offer code available for Save $5 Off Your Shopping Cart with Code at National Geographic Online Store (Site-Wide). Click the blue button to copy this promo code to your clipboard. Then, place your items in your shopping cart at shop.nationalgeographic.com. Finally, enter the code in the coupon code box during the checkout process, and your savings will be applied.
Levenhuk is running an offer code for 10% Off w/ Promo Code on Your Order at Levenhuk, redeemable at their site. Click the blue button to reveal and copy this discount code. Enter this code in the promo code entry box during checkout at levenhuk.com. Your discount should be applied.