During my own e-com venture, I had the opportunity to validate a couple of e-commerce platforms. Below I share my personal views and I hope you find them informative.
Gumroad
Offers free buy-button for digital and physical goods. Gumroad let you set up product cards and embed them on any web page/email/post you want, moreover, you do not pay anything unless you sell your products. They take a fee of 8.5% + $0.30 (USD) per sale. You can also upgrade to a paid premium $10 per month plan plus 3.5% + $0.30 (USD) per sale, which is comparable to the previously paid plans, especially WordPress premium plan.
Best for: Creators, artists, and anyone with a couple of products physical or digital. Also, it is the best way to start with zero cost when you don't know if you will be able to sell or not and you want to be free to sell on many different websites and platforms.
Onecheckout
Offers Free buy-button for digital goods and services. It uses the well trusted and known provider Stripe for payments. The fee is the same as Gumroad but you get a sleekier onboarding, and a modern minimalistic look on your shopping pages 😎.
Best for: Anyone with digital products or services. If you are new to selling online or you simply want a quick, easy onboarding and selling experience Onecheckout is a good choice.
Shopify
A well-known platform, with modern UI/UX and easy setup. It is best for people who already own a business such as a physical shop, they have revenue and want to go online. The price plans start with the Lite $9 per month and this is for just making a buy button here and there without any access to most of the features the platform offers.
You actually get the best of the platform with the $29 plan per month.
As with all platforms, it integrates with Paypal, Stripe, and many more payments providers. Bear in mind that they also get a cut from your sales or a fee, so when you decide which one to use read the details of how it works.
Best for: Someone who is already selling products or has some revenue, otherwise you will be in monthly dept.
Ecwid
Another known platform which basically competes with Shopify and for the same shop you pay ~50% less. If you want to have a full online presence and pay less then Ecwid is a good option for £15 per month.
Best for: If you want to sell online and be professional but you are unsure of your revenue you can even start for free and commit to a plan later when you increase your sales.
BigCommerce
By visiting the website it is clear that this platform aims at bigger brands and businesses. If you start now it's not the most cost-effective. For example, the plans start with almost $30 per month, which sounds as an alternative to Shopify's plan.
Best for: Keep this in mind for the future, when your brand and business is ready to go big.
WooCommerce
This another popular choice which is free and works with WordPress sites. There is a catch, however. If you want to use it on your WordPress site then you can install and use the plugin only at the WordPress Business plan which comes at a $20 per month cost. So basically you have to pay Business plan on WordPress.
Best for: Anyone who is already on WordPress Bussiness or higher plan.
WordPress
Okay, WordPress is not exclusively e-commerce but on their Personal plan £3 you can accept payments one-off or monthly if, for example, you sell services, online courses etc. On their Premium plan at £7 per month, you can use the Paypal button to even sell products/services on a regular basis.
Best for: If you sell a small range of products or services and you want to spend less than Ecwid then WordPress is a cheaper option.
Free options with an applied fee only after you sell something.
Etsy
Easy to onboard and sell your physical products/crafts. It's free and you are only get charged when you sell something.
Best for: Crafts and hand made products. Better use it if you don't care about creating a stand out brand and you are confident you will be discovered amongst the other products.