The soluble filament is something that Stratasys developed and other companies are only starting to match. Airwolf is one company that's supposed to have a comparable solution (I haven't tried it myself): https://airwolf3d.com/shop/water-sol...port-3d-print/. As Aardvark says, you need a dual- extruder printer to print support material as well as the part itself. Printers at the ultra-low end of the market don't come with dual extruders. Stratasys machines cost about 100 times what you're looking to spend; the Airwolf machines are only about 10 times that.

3D printer companies have talked for some time about making their machines recycle unwanted parts into new filament, but so far I haven't heard of one that was actually on the market as a recycling printer. There are various machines like the "filastruder" which can produce filament from raw pellets, but they don't include a grinder for recycling. There are other problems with that idea, like contamination, and the tendency of plastics to fatigue after multiple melts.