There are several affordable platforms for starting an online store, similar to Shopify. Here are a few options:

1. WooCommerce: WooCommerce is a popular e-commerce plugin for WordPress, making it easy to set up and manage an online store. It's open-source and free to use, although you may incur costs for hosting, themes, and extensions.

2. Big Cartel: Big Cartel is a simple and affordable platform designed for independent artists and creators. It offers various pricing plans, including a free plan with limited features and paid plans with additional features and customization options.

3. Square Online Store: Square Online Store integrates seamlessly with Square's payment processing and point-of-sale systems. It offers a free plan with basic features and paid plans with advanced features like inventory management, shipping integrations, and marketing tools.

4. Wix: Wix is a website builder that includes e-commerce functionality, allowing you to create and customize an online store with ease. It offers a free plan with Wix branding and limitations, as well as premium plans with additional features and customizations.

5. Ecwid: Ecwid is a versatile e-commerce platform that can be integrated into existing websites or used as a standalone online store. It offers a free plan with basic features and paid plans with advanced features like inventory management, multi-channel selling, and abandoned cart recovery.

These platforms vary in terms of features, pricing, and customization options, so it's essential to evaluate your specific needs and budget to choose the best option for your online store. Additionally, consider factors like ease of use, scalability, and customer support when selecting an e-commerce platform for your business.