@Lucas E both new and used, most of the new models were $200+ but firebrick and I found a few used and new on ebay for $75-$100 which isn't bad, the shipping to Alaska was the killer for me.
There are a bunch of different ones, trabon, lincoln, bijur, lube usa are the ones I saw the most. Specific models depend on your application and amount of ports needed. Do a google or ebay search for progressive valves, it should bring up a bunch.
I was going to be using the Chinese manual one shot that came on my 833, but there are motorized pumps from all of those companies you can get. I don't think all of the vale blocks will work with a manual unit since some of them had a 200 PSI req pressure to actuate the pistons inside.
For what its worth I will probably end up making a manifold and use individual metering devices for each port. until then I'm going to use what I have and design a new system for longevity and performance vs a thrown together hob goblin'd setup.