"Does it only come in the form of an oil?"
CBD, or cannabidiol is a naturally-occurring cannabinoid found in medical cannabis. Usually in much lower concentrations than THC. Commonly, it can be found in the form of cannabis-infused oils, like olive oil or coconut oil. These are referred to as tinctures, and there are many different brands, strengths and prices. They are nice because you can adjust the dose drop by drop. There is a processed form of CBD which is made into a CBD crystalline (powder). CBD is also made into time-released capsules, infused water, and even a transdermal patch where you can absorb 10 mg of CBD through skin. -LG