The shopping cart page is a common place to showcase your current promotions. Not only is the shopping cart (typically) less visually cluttered than your home page, a visitor that views his or her cart summary is closer to becoming a customer than on any other page on your site, save the checkout process itself.
You may have banners throughout your site that showcase your special offers, but often customers have a short attention span, and reminding them on the cart page can boost the response to your offers (and average order value). Banners are the typical way to display your last-minute reminders, but are they the only way or the best way?
Banners in the cart
Here's an example of a banner-style promotion from Bath and Bodyworks:
The problem is sometimes these banners are overlooked due to the "banner blindness" phenomenon.
Floating promo boxes
A more in-your-face approach is a floating promo box that descends from the top of the page, as Victoria's Secret uses:
Bath and Bodyworks uses both a banner and a floating box:
The tricky thing about anything that floats or pops up is it could be very irritating to customers. Novice users may not even be able to close the box, get frustrated and abandon cart. On the other hand, they can really get attention and lift sales. (If you've tested this, we'd love to hear your war stories in the comments.)
Promos in the content space
Another more subtle approach is to show the offer in the cart summary's content area where it's more likely to be read, like Target:
Unfortunately Target's Buy One, Get One 50% off promo is not clickable.
French apparel retailer Kiabi has a creative tactic - include a call to action button right in the cart summary that lands right on the page the "BOGO" offer applies:
It's important to maintain "scent" (relevance) between an item's promised offer and the cart summary. Unfortunately, American Eagle does not maintain scent between the BOGO offer on the product page and the cart summary, rather it shows a completely different promotion in the cart:
Testing your promo tactics
If technically feasible for you, consider testing 4 versions of your cart summary and find what works best for your site:
1. No promos, just cart summary.
2. Banner promo.
3. Floating box promo.
4. Clickable promotion in order summary box.
We'd love to hear about your test results in the comments!