Depends on your size of operation as to how hard or expensive it can get.
As a home/hobbyist I built my hood from plywood and some scrap plex-a-glass for a front hinged at the top. Only thing I bought was a decent fan. Painted everything good with latex house paint.
For a small scrubber system you can make one easy enough for not much money. I bubble my fumes in series of vacuum flasks with peroxide. Capture the fumes on the digestion beaker with a plastic funnel upside down for a lid, tubing on the funnel and into the flasks using an old aquarium pump to pull the vacuum.
When not digesting or otherwise creating fumes I can use the flasks for other things, like vacuum filtering.
Several members here have posted some home made setups that work very well. Search around.
