Usually I have the same problem when I build some test benches for the machinery.
The cheapest solution is to buy a digital voltmeter , disassembly the protective box and install it on the front panel.
So you have a already ready input attenuator and different measurement as needed ( voltmeter, ammeter, ecc )
If you need galvanic separation a 1W DC-DC converter is enough cheap ( credits to a greek friend of mine, S. Liodakis for the original idea ).
The cost of a digital voltmeter is actually about 10 Euro.
Mandi