I have a refurbished Samsung Galaxy Tab with no Android Market App I bought a refurbished Samsung Galaxy Tab running
Android 2.3.5


There is no app for Market on the phone. 
When I get to market directly, it only shows my Iconia and I've already downloaded things there that I also want on my Galaxy.
When I'm told to sign in to google account, it says I can't add that account, it's already there. I'm not trying to add it, I'm trying to sign in through the google system.
Skype will not download, either.
Have you tried installing the Market?  I've installed the 3.4.4 Market from Android Police a few times, if you're looking for a safe file.  Just put it on your SD card or internal storage (make sure it has the .apk extension) and install it via a file manager.  Settings -&gt; Applications -&gt; Unknown sources needs to be checked for this.