I just had a try with an old guitar tuner, a QUiKTUNE, and found that that works for voice too. But you do have to hold a note.
It is one of the old-fashioned electronic ones that you put on your knee to tune the guitar, with a gauge for the note, and it also will play the note. Just the standard guitar open notes, of course, E-A-D-G-B-E.
It cost about US$12 when I bought it 10 years ago. You might find one on EBay.
There are other tuners that do the full scale. They are more expensive, but possibly nearer to RTim's requirements. You can also get free guitar tuner programs for the computer.