This Heathkit PS-3 Power supply has a range of 0-500 volts d.c.
I have it set to about 200 volts to light up the IN-18 nixie tubes. As you can see,
even the nixie tubes say $30.

It is an older Heathkit Power Supply from 1958. It has 7 tubes inside and a large transformer.
It probably can use a re-capping of the filter caps but it works fine as is.

It is set to 500 volts. You can flip a switch to read how many milliamps your circuit is using.

Rear of Power supply. Its a little dirty and has a slight dent from shipping on the front.

Here is the specification sheet. I loaded it to 100ma at 300 volts with no problem.

Here is the schematic. I will send/email a scanned copy of the manual with the power supply.