There are four categories of costs to consider.
1. Subscription: This is a fixed monthly fee you pay to use Shopify's platform, which is $29 USD per month for their basic plan.
2. Themes: Websites use templates or themes that determine the look of the site. Shopify offers free and paid themes. Free themes are a lot weaker when compared to paid ones and you might have to rely on paid apps to make up for lack of features. Paid themes are a one-time fee and the cost ranges from $100-$300 USD.
See the Shopify theme store.3. Apps: Shopify offers over 5,000 apps for all your needs. These apps range from free to paid. Paid apps are usually monthly subscriptions. Some functions from paid apps are included in paid themes, so the extra initial investment prevents you paying monthly. Many merchants purchase apps as they offer more functionality for your store, such as analytics, fulfillment, customer service and more.
Browse Shopify apps.4. Transaction fees: Shopify does not charge you transaction fees if you use Shopify Payments (which is free to use and only
available in certain countries). However, you are still subject to pay credit card fees. These fees apply regardless if you sell on Shopify or any other platform and they go to the payment processor providers.