Transponder Help

The used ones are $500 - $700 & a new one $1125. I lost my job &
would like to keep the costs as low as possible. If I bought a used
one would I be spending more money repairing it in the future? If I
spent more money for the new one is it any more reliable that a
refurbished one?

There's no way to predict, you can only play the odds that a new one will
last longer and require less maintenance than a used one. My advice - buy a
used one that passes a bench check. In the future when you have a job and
can afford it, replace with a new one if it craps out.

Or you can just go transponderless for a while, nothing wrong with that if
you can accept its limitations.