I'm not sure about how much grain they can hold, no volume amounts are given on the website, but most definitely "YES" on the question about saving money if you buy it yourself. (I might be missing something here, I'm shocked that the shipping is 100lbs for 2 coolers)
It will of course vary depending on the cooler you buy, but as a rough estimate:
- 2 Coolers - 60-70 bux
- 2 ball valve setups - 30ish
- Silicone Tubing - 20-25 (2.00 a foot from MoreBeer)
- Manifold - 10 bux (Instead of a false bottom you could easily make a manifold from copper, cpvc, or a stainless hose braid.
- Sparge arm - 5 - can make something out of left over parts from manifold
So at the high end, maybe 140-150 to make it yourself. However, I suspect you can make it much cheaper, I'm just guessing on the prices. As far as the tools required, you would need a hacksaw or copper tubing cutter to make the manifold, a drill and a small bit to drill holes in the manifold... that's about it.