This is from there site about coupon codes

Discount Coupons

We regularly offer discount coupons to our customers through our email newsletter. Offers are good for a limited time only and are not retroactive. Each coupon can only be used once. Coupon codes cannot be combined with other coupon codes or offers.

If you have not already subscribed to our email newsletter, you can change your subscription options on the following page:

https://www.amainhobbies.com/account_newsletters.php