You need to use malt extract for your starters, because you want to acclimate your yeast to eating the more complex sugars, rather than the simple ones like corn/table sugar. Otherwise they'll go for the simple sugars and not be able to break down the more complex ones in your wort.
If you can't get to a lhbs for dry or liquid malt extract, find the nearest Mexican grocery or even the nearest big box grocery store (like Meijer's) that has an "international foods" aisle and look for Malta Goya
Or Malta India
Quite a few people use it as a starter....It is pretty much just a lightly hopped, carbonated wort. Some people just stir it to release the co2, others bring to a boil and other's just bring it pasturizing temps. ANd then pitch the yeast.
There's a few threads on here about malta goya starters, both here and on other boards (google it)...and we even talked about it in the GAP (Grocery and produce challenge thread)
Another option is to head to a bed bath and beyond or even a big box store that might carry mr beer refill packs and buy one of them..you can use the can of LME as his starter extract.