Note that the separate DC supply to power the meter must be TOTALLY isolated from the voltage being measured. That's a key point!
If you do a search on eBay for the exact title below, the top result that comes up is a suitable meter, and they have it in the proper voltage and current ranges.
Red LED Digital Digit Voltage Voltmeter Current Ammeter AC Meter Panel 3 1/2
Here's the drop-down that shows you all the varieties available. You'll note the 0-10A and 0-20V meters are there, ideal for most layouts.