I am trying to get set up to start selling at craft shows and would appreciate any advise on buying a tent and table covers.

Google “tents and table covers for fairs and festivals” and you will find a large range of prices and styles.  Also, some of the events will rent the basics to you.  Check with the promoter or contact listed to see if they do.
Good luck.

I bought my 5’ and 6’ folding tables at Walmart.com.  They have pretty good prices, but do a quick google search before you buy, just to be sure.

For linens, I went to Joann Fabrics and bought 120” of fabric that was 60” wide.  It covers the top and front of my 5’ table after I hemmed the edges.  It was a lot less than a nicer table cloth online and in the particular color I wanted.  I prefer having the back of the tables open so I can access my storage however, but that might be a deal breaker for you.

I tried buying linens online through some discount company and was super disappointed with the quality.  I couldn’t get the wrinkles out and it made the whole display look unkempt.  So I switched back to my homemade table clothes and haven’t looked back since.

Good luck!