Hi @DCBD,
Welcome to the Community.
My first thought would be to have a flow filter that excludes these subscription customers. However, that requires your integration/whichever method you are using to store this info to pass on a property about a customer that has a subscription. For example. I would add a flow filter that is the same as a segment: "Properties about someone > Shopify tags > contains > Active Subscriber." could be used if you have a Shopify integration.
Another way would be with ReCharge. When a profile has an active subscription, we add a custom property on their profile called ReCharge Subscriptions, which includes a list of any subscriptions that they currently have that are active. When they cancel, these values are removed and the ReCharge Subscriptions property would be empty if they don't have any active subscriptions. The filter you'll want to use on your flow looks like this.
With this filter, if anyone has an active recharge subscription or purchased, they will be skipped on this flow. Just note that the "Type" needs to be turned to "Text" to select "Is not set".
an example:
I also recommend taking a look at these Community posts as they could provide some info on this setup.
Hope that helped,
Alex