raffike, you are right about getting mechanical vacuum for $500. but let me show you the benenfits of a recirclating vac station;
1)good reliable performance, dont have to worry about changes in vac due to toilet flush etc.
2)no oil need to change, if you have an over flow on your rez then have that go to the drain while lines from say your condensor line supply the water
3) relatively quiet if you have it set right; put the aspirators so the water exhaust is below water level, only noise should be jet pump.
4) finally one of the best indicators is the end result, it pulls ketone over 145-160C, and no need to ever do any maintenece, or rebuilds etc.
Vac source being an important lab tool not only for distilling, vac filtering, also vac drying; please share your experience with me in order to umprove vac performance. I've heard of bees pulling ketone at 100C here at the hive. Imagine the yeild improvement