You don't really want to use any simple sugars to make a starter: the yeast will consume them and multiply, but they also will lose the ability to consume maltose - which is the majority of the fermentable sugars in your wort, so that's a bad thing.
I honestly can't think of anything from the grocery store that would be really good. I mean, maybe you could do something with that Goya Malta stuff. . . but I wouldn't recommend it.
Starters are really great ways to improve your final product, but they aren't necessary to make really excellent beers. The vials and smack packs come with more than enough cells to ferment a five or ten gallon batch, so you can just pitch directly from one of them: I've won more than a few competitions pitching a single vial into five gallons of wort, so don't imagine that you're beer will automatically be BAD if you do that.
So, in short: my first choice would be for you to get some DME, some LME, make a mini-mash, or whatever you have to do to get some real wort. Short of that, just pitch a vial, and don't screw around with making a starter out of wheatabix.