Right now at Amazon, you can add an item of your choice from a selection of athletic shoes and apparel to your cart and automatically receive 25% off during checkout. This only works on one thing, and you can only use it one time. The selection is huge, though, so it is definitely worth checking out. A lot of the items are already discounted too which makes the extra percentage off icing on the cake.
Note that some accounts aren't eligible to receive this discount. It worked for some Team Thrifter members, but not others. Your mileage may vary but it's definitely worth checking out since you can shop such a large variety.
For example, the pictured highly-rated Adidas Men's Matchcourt Sneakers fall to $37.98 shipped after the discount is applied. This style has sold for as much as $70 in the past.