If you were on a trip to stock a paleo kitchen you could buy:

Refrigerated departments (or buy from specialty stores):

fruit
vegetables
fresh meat (without nitrates)
fish and shellfish
eggs
orange and some other juices (100% juice only) [not really paleo]

Store Interior:

coconut milk (try for Thai Kitchen - no preservatives)
Thai curry paste
water chestnuts in water (paleo? use for what?)
olive oil, preferably first cold press
Starkist "Low Sodium - Low Fat" tuna, or tuna in olive oil
other canned fish in olive oil or water, preferably no salt added
tomato paste/sauce (must not have flavorings or natural flavors, nor salt)
unsweetened applesauce ("natural")
spices
green tea (or loose at the HFS)
bottled spring water

Health Food Store:

seeds
nuts (raw, but not cashews or peanuts)
nut butters
dried fruit (raisins, apricots, cherries, dates, etc.)
organic fruit and vegetables
unsweetened coconut flakes
coconut oil (or in Indian market)
tuna
honey (optional, raw unfiltered only)

Mail Order:

nut flours (almond, pecan, and chestnut)