Hey @Bryan1311 quick heads up, be careful with the first poster Cork Labs, they’ve been caught breaking Shopify terms of service, violating FTC laws, and posting fake positive reviews on their apps and fake negative reviews on other apps. Reference: https://speedboostr.com/fraudulent-shopify-partners/#copyright-cork
When you install apps they can access your store’s data, I personally wouldn’t want a shady company that commits fraud to access my business, so giving a friendly heads up.
For your solution, since you’re getting into dropshipping it might be worth searching dropshipping apps in the Shopify app store to see if something provides more solutions for your system: https://apps.shopify.com/search?q=dropship
Aside from that, our app Order Automator has a strong history of helping stores work with dropshippers by sending order data to them (in emails or csv).
For calculating shipping costs, you’ll want to do that before they place the order… a solution that comes to mind is to set each vendor’s product’s weight to be unique, then calculate shipping by weight.
Another idea is to make each vendor have its own location - by default Shopify charges shipping for each location in the order, so if you have an order with 2 separate locations, they’ll get charged shipping for each.
A 3rd idea is to average your shipping costs and charge a flat rate. This is my preferred method because it’s easier for everyone + it’s straightforward for the customer. You’ll likely have a higher conversion rate when the shipping is known, rather than a surprise (in studies I’ve read about 30% of abandoned carts are because of unexpected shipping charges).