Yes you can build your marketplace app with StoreHippo at ZERO additional cost. You just need to pay for your monthly subscription.
With StoreHippo mobile-ready ecommerce platform you get the following features to build your marketplace apps:
You can check detailed mobile commerce application features here.
You can find detailed guides to help you build your mobile apps here.
Along with these we also have 300+ inbuilt features for handling end to end ecommerce.
You can check the platform and features by starting your 14-day free trial store