Environmental activists and concerned citizens have long been considering the effects of disposable cups on our environment and our wallets. It is often necessary and convenient to use disposable cups. This changes the debate from reusable vs. disposable cups to Styrofoam vs. plastic cups.
If price is your main concern, plastic is the less costly option. It is lighter, which makes manufacturing and shipping less expensive. Styrofoam is a little more expensive to purchase, but it does double as a hot and cold drink cup, so it may be more cost-effective in the end, depending on your intended use.
Styrofoam insulates much more effectively than plastic, which means your cold drinks stay colder longer and your hot drinks stay hotter. Plastic cups are not recommended for hot drinks, and they do not have the insulation properties of Styrofoam.
Styrofoam is not biodegradable and cannot be recycled, which means that Styrofoam cups contribute to landfill trash. Chemicals are also used in the production of Styrofoam, such as benzene, that environmentalists claim are harmful to the environment. While plastic cups are not biodegradable either, many of them are recyclable, which does make them the more environmentally friendly option.