I don't understand why someone thinks you need ( cushioning) in your table cloth, I've used, handled, seen literally thousands of tablecloths-- all of which were simply one layer of fabric. The only reason to back one is to protect the seams if it is pieced, and then you need to quilt it to hold the two layers together

I think you really only need batting if your top has some thick seam intersections - the batting would help cushion that so it's not like little pebbles when you try to set your glass down.

If your pattern doesn't have that issue and you're not worried the backing will show through, I'd say just skip the "middle" and have it just be a top and backing. Save yourself some money and hassle!

I would buy some inexpensive (like, $6 a bag inexpensive) poly batt from Walmart and just use that. I know a lot of folks like to use flannel but I tell you what - it's hard as heck to get nice tension with that thin of a sandwich. Flannel is cheap so it's a good alternative, but I'd spend a wee bit more and get a cheapie batt. Get low loft if you don't like that cushion...you can flatted it more with added quilting. You'll shave a lot of time and frustration trying to achieve and keep good tension. IMHO ;)

For the record I'm totally not a batting snob. Unless it's going into a show I use those poly batts all the time. :)