Viral Store now give you the option to add a banner using AdHero.
If you have AdHero account, you can easily integrate your Adhero banner to your Viral Store account. Simply copy your AdHero code and paste it to your Viral Store settings.
You can integrate two sizes of banners and one banner for each size.
Here's where you can integrate the banner:
If you have trouble adding a banner, feel free to submit a ticket.