How much do you spend on formula every month for a baby who is on dairy free formula?

I haven’t used formula in 9 years (my second had to use special formula when he was a preemie) and so I have no clue what the cost is nowadays.

I have exclusively pumped for 6 months and I am barely keeping up with him and having to thaw about 5oz a day to add in . And my stash will probably be gone in a month so I’ll have to start supplementing or stop pumping all together.

So if you baby is on dairy free formula, how much do you spend per month? And what brand?

Thanks!