Shopify is what I used to use for my e-commerce business. It is an affordable option with several helpful plugin options. They are currently offering a 90 day free trial.
If you have a dropshipping store with Shopify, this app is a must have. I used this app when I was dropshipping through Shopify. Free plan available.
Spocket is the best dropshipping app for products sourced strictly in the USA and Europe, therefore leading to shorter shipping and delivery times.
AliDropship is the best WordPress plugin for AliExpress dropshipping. This is what I now use since I've switched over from Shopify to WordPress.