I have looked everywhere for it. Publix Supermarket, Wal-Mart, Target and I cannot find it.

Where can I purchase a bottle of Malt Syrup?

I have a heck of a time finding it in stores. Try a health food type store, perhaps?
King Arthur sells it online for a fair price, though:
http://www.kingarthurflour.com/shop/items/organic-barley-malt-syrup-16-oz

In use it for breads and bagels. I found mine at Whole Foods next to the various sugar and honey stocks. It may also be called malted barley syrup. You may also be able to find it at the local home beer brewer's supply store. I know they sell barley malt as a powder.

homebrew store!! or local mega liqour store that sells homebrew supplies. you can get the syrup there or powder form.

I recently bought Malt powder (Carnation makes it) and I've used Ovaltine Malt powder, plain & chocolate. I put several TBSPs in a measuring cup and add some hot water to make a syrup. I've found it in the grocery store near the powdered drink mixes.

I add it to buttercreams, both vanilla & chocolate, and to chocolate Bettercreme mousse for filling.

HTH
Rae

I do the same as Rae with the powdered malt, but I mix it with warm half n half. It is sweet though!.it's great mixed into IMBC or SMBC.