Ralph Mowery wrote:

For about $ 20 you can get a single electronic ballast that will run all
4 tubes. Then put in the newer T8 bulbs.

You will have to follow the wiring diagram that is on the ballast as it
will be different from the old one. The new ones are made to fit in the
same bracket/screw holes as one of the older ones.

Thanks for that suggestion!

How does this one look from Home Depot?
http://www.homedepot.com/p/120-Volt-...3885/205409893

One question is whether I need "instant start" or "programmed/rapid start":
https://www.1000bulbs.com/category/4...cent-ballasts/

I think I need "rapid" start because that's what is there now, I think.

Since cost is a major issue for me (I have little money but want to get rid
of the buzzing from the bad ballast and if I can get rid of fluorescent
tubes and save money on electricity, that would be a plus), here's the cost
breakdown:

$20 for the T8 electronic ballast
$28 for the four T8 LED bulbs
-----------------
%50 roughly, for the retrofit

Is that my best option?