There is no limit to the number of subscriptions a customer can purchase in one order. Once a customer has added a subscription to their cart, they can continue shopping as they normally would and add more products to their cart. These can be one-time purchase products or additional subscription products.
Customers and store owners can also add additional products to existing subscriptions using Bold Subscriptions' management tools. For more information, please visit the following articles:
Additionally, you can enable the Express Add-Ons Widget to allow customers to quickly add additional products to their existing subscriptions while shopping on your storefront.