When the pcm went bad in my 2008 F450 (v-10 gas) I had a heck of a time finding one. Took me 8 months because failures are very common in those years so demand is high while supply is very low. The replacement part number must match the old one exactly.
There are several companies online which claim to rebuild them but most are plagued by bad reviews if you dig. Flagship One is probably the worst. I spoke with at least 3 different people personally who said that dealing with them was their absolute worst purchase experience ever. Unfortunately they were the only company that had mine in stock when I began looking. They wanted $2700 for it.
Thankfully my problems did not prevent my truck from running. My AC would blow hot half the time, my alternator light came on whenever it wanted and I had several OBDII codes but the truck still ran. I eventually found one on eBay for $1800 from a seller with excellent feedback and I took a chance. I have never bought anything on eBay before, didn't even register. I bought it as a guest. I sent the seller a message to hopefully convince him I wasn't a scammer and a week later I got an old, used PCM in the mail. I took it to my mechanic because it had to be programmed into the truck for it to work. That was 6-8 months ago and it has been perfect.