Lt1 oxygen sensor simulater
 

So are they worth the money?

They're used in lieu of the post cat oxy sensor to fool the computer into thinking the cat is still there, when it isn't. Is it worth it? It's that or get that part tuned out of your computer to get rid of the check engine light.

I bought 2 different ones. Neither worked. I stll had a SES light and corresponding codes. Get a tune to eliminate the back sensor.
Interestingly enough, you have a 95. They don't have the post cat sensor. You need the O2 sensors on a 95 for the computer to control the fuel ratio, therefore they can't be eliminated.

I had a feeling he may be thinking of using a simulator in place of the pre-cat oxy sensor, which you don't want to do.