If you need grains now, your best bet is just bite the bullet if you're intent on buying a sack of base grains. What I do is buy maybe 20-30lbs of a base grain(s) and/or other goodies to take advantage of a vendors' free shipping policy if it's offered. It's not like buying a 55lb sack of pilsen malt, but you could do 20lbs here, 10lbs there, etc, etc to float you by.
I'd call the closest shops and see what their prices are vs online with the expensive shipping. Like Hoppy2bmerry mentioned, it could be cheaper to drive to the shop and get it vs having it delivered.
Until then, join a homebrew club. Some LHBS give club members discounts on ingredients. A shop near me gives me 10% off. Unfortunately it is about 1.5-2hrs out from me.