How can I format a value as a number in a Excel formula that includes text?

First time poster!

I have two tables of information: The top table is a product price index. The bottom table is criteria for how the cost for a product can be split into monthly payments.

Picture of Tables

My goal is to develop a formula that will automatically calculate the correct number of payments and the correct payment amount with the correct processing fee applied). I figured it would be best to reference cells instead of values so that, in the event pricing/minimum purchase amount/processing fee changes, the results in (C2:C9) will automatically update. Here is the formula I've come up with to calculate the monthly payment for Product A:

=@IFS(B2>=B16,"5 Pay = $"&ROUND(((B2+C16)/A16),0)&" + tax",B2>=B15,"3 Pay = $"&ROUND(((B2+C15)/A15),0)&" + tax",B2>=B14,"2 Pay = $"&ROUND(((B2+C14)/A14),0)&" + tax",B2>=B13,"1 Pay = $"&ROUND(((B2+C13)/A13),0))

My challenge is that I'd like the payment amounts in C2:C9 to be formatted as numbers (with commas, EX. 1,979 instead of 1979 for cell C8).

I'd appreciate any help you all might offer.