Mapping incremental code after iterator into single body

Hi everyone - I’m new to make and need a little help. Screenshots are below.

My setup is this:
Step 1 - Webhook from a sale
Step 2 - Iterator takes all sales products from payload
Step 3 - HTTP request to get info for each payload
Step 4 - Each product is created in stripe and each product gets a unique “price_id”
Step 5 - Each new price_ID variable created in step 4 gets put into a string with increasing positional numbers as it repeats. This step is where I’m having an issue.

The input, as referenced in the screenshot - would have the following in the body:

I need a line of that to appear for each one of the products created in step 4, with the bracketed number ([0] and [1]) to increase by 1 for each new entry. Furthermore, the “XXX” variable would need to be the Price_ID created in each step in step 4. If I have only 1 product, I only need one line to be added into the body of step 5. If I have 6 lines, then I would need 6 lines created with the bracketed position item to say [5].

I appreciate all input.

I believe you could use the variable bundle position from the iterator.