You can find some eo's in health food stores. The reason most of us prefer to buy online is price...once you find an eo you like, they are pretty similar every time. 1/4 ounce of something at the health food store might be the same price I pay for 8 ounces online, no kidding!
Some nice staples to have: Orange, lemon, lime, grapefruit, peppermint, spearmint, wintergreen, cinnamon, cloves, lemongrass, eucalyptus, patchouli. Ok, I'm a fragrance nerd!
Ok. 2 cents:
I really really really hope that the wintergreen you're talking about is not an essential oil. Wintergreen essential oil smells delicious, yes, but it is NOT SAFE. The main constituent of the oil, that gives it that wintergreeny fragrance, can cause severe liver damage, even if you don't notice any ill effects.http://www.aromaticsage.com/poison.htm
I am not trying to fearmonger or anything here. Using wintergreen-containing pain balms every so often is probably ok, for example. I used to use it myself before I read up on it. But it is one of the oils home users are strongly recommended to avoid.
Others to avoid include (not that you would want most of these for their scent):
Anyone using essential oils in B&B should also be careful about photosensitizing oils used in products left on the skin, like lotions. Most notably citrus oils (bergamot, lemon, lime, tangerine, etc) shouldn't be left on the skin if you're going to be in the sun later, because it increases your risk of burns. (Note that the oil itself doesn't cause the burns, it just increases your susceptibility to UV rays.)http://aromatherapy.suite101.com/article.cfm/photo_toxic_essential_oils
Essential oils are great, and I use them every day, but you have to be careful careful careful with some of them!