To connect Sage 50 with Shopify you can use Zapier and the Commercient connector.

It is pretty simple and doesn't use coding. In Zapier you create a "zap". A Zap is made of two parts: a trigger (the thing that starts the wheel rolling) and the action (the result you wish to take). It sounds to me like your are lookging for something like this: When an order is created in Shopify (the trigger) import the order into Sage 50 (the action).

With Zapier and Commercient for Sage 50 you can decide on your own workflows in a point and click fashion, no coding necessary. There is a free beta program from Commercient that just opened up to use Zapier to connect Shopify and Sage 50. The Commercient product is called the Commercient IoT Gateway. Here is the link for the beta access: www.commercient.com/.../
Good luck, your use case is solid so you have a good chance of being chosen for the beta.
JB - Commercient

Britt has probably long since moved on to find a solution, but here is quick note to anyone crossing this thread with the same need. Long-time Sage 50 partner CartSpan now supports integration with Shopify in addition to 20 other popular eCommerce platforms including WordPress/WooCommerce and BigCommerce.  Additional information can be found at Sage Partner Solution Source.

The benefit over other platforms mentioned on this thread is that the integration doesn't cost more than your accounting software itself and also has much deeper/robust functionality.

Thanks,
Scott Wheeler

What I found really helpful was this app called Storehub.io, it sets up really easily and allows for pretty much most flexibilities that one may need when connecting Sage to your Shopify eCommerce store.

I think they also have a B2B platform which caters for complex pricing, multi-warehousing and sales reps. There's a lot more to it, but definitely take a look at what they offer: www.storehub.io.

They've got a reseller program as well, which is cool for us developers/designers who are referring customers to them.