1996 Panasonic CT-31422SFT color TV. The picture shrinks and fluctuations size vertically, that is the picture gets narrower, up to 3 inches per side. This is intermitant. Usually it fluctuates after turning on. Sometimes after a while it will stop, then after a while restart. When it shrinks, there is a red/yellow color shift or "smear".Recently, it stuck in the narrow size and darkened. It has been doing this for about a year. ONe shop suggested unplugging it for 30 minutes to allow it to reset. That helps but does not solve the problem.

Now it not only is shrinking vertically but also intermitantly horizonally (top edge of picture in dropping).

Does this sound like a power transformer or high voltage circuit problem?

About how much should I expect a repar to run, in the Denver, Co area?

Sounds like a cold or broke solder connection. A repair shop will likely take apart, visually check bottom of circuit board for bad connections, bad connections will also sometimes cause the board to be dark arount that area.