I've shot with a couple of Nikonos cameras the V and III models. My grandfather had the Nikonos I, II, III, and V over the years. Additionally there were a great line of underwater cameras by Sea&Sea. They are still around and now are a manufacturer of the high end housings mentioned above.
If you are just looking for splash proof and dust proof rather than Dive housings look into some of the waterproof bags for an affordable alternative.
I keep these (
https://optechusa.com/rainsleeve.html ) in my camera bag as insurance for a rainy day, they are super light weight and work well for keeping a light rain or waterfall mist off the camera. Also work well for keeping frost / dew off if doing overnight timelapse shots. Basically it's a dry cleaning bag shaped to fit over a camera.
Next step up is a water proof dry bag, There are a bunch of these on the market and they seem to be getting better every year. The early ones had rather crappy lenses, a stiff feel and difficult access to buttons. Newer ones like (
https://www.bhphotovideo.com/c/product/612831-REG/ ) have improved on many of these issues. and are still under $100. I've played with these but don't own one because I've yet to find one that can be used on a tripod. They look great for surf shots, kayaking etc... but I doubt I submerge my Nikon in one.
Then there are the Outex setups (
http://outex.com/waterproof-camera-covers-products/ ) These are very flexible. Use optical quality glass, good button feel, and offer tripod support. The cost is higher than the bags above and depends on what size camera kit you are protecting. To protect my Nikon with grip and a 77mm lens the cost is just over $500.
Boort