@LilAngel What are you looking to do with the Etsy integration? Shopify does integrate natively with eBay although the functionality may be limited.
There are also apps you can install like http://apps.shopify.com/trunk which can help you sync inventory in real-time between Shopify and Etsy + eBay
Hey Lil Angel.
I believe you are looking for a solution that integrates your Shopify Store with Etsy Marketplace. You can check out following solution - https://apps.shopify.com/etsy-marketplace-integration The solution will help you not only list your product to Etsy but would also automatically update your price and ivnentory with Shopify.you can also manage your Etsy order and shipment from Shopify.
If you are looking for a solution for ebay , then you check it our over here - Ebay Solution on Apps Store
You need to have an active Shopify Store which is the very first requirement. You also need to have a seller account on Etsy Marketplace where you want to list the products. You can directly install the app from Apps Store once you are signed into your Shopify Store - https://apps.shopify.com/etsy-marketplace-integration
For more queries related to the App post installation you can send an email to the development team at email@example.com and you would get the replies.