I have a question about using inline code in the logic app. So, I needed to manipulate incoming json data and I created an integration account under free tier for the same, so I could use Javascript inline code. Is that a good option or creating an azure function and calling that from the logic app?
In my opinion, use integration account is a good solution but it depends on your needs.
If you just want to do some simple manipulation of the json data and you can implement it in "Javascript inline code", "Javascript inline code" is a good solution because you can create an integration account in free tier. If you do it by creating azure function, you need to pay for the plan of the function app and also need to pay for the storage of function app. When you call the function in your logic app, you also need to pay for this connector running.
But if you want to do some complicated manipulation of the json data which you need to write complex code and you can't implement it in "Javascript inline code", I think you'd better to create azure function for your requirement. You can create a function app with consumption plan to reduce the cost.