The convenience store industry sells over $500 billion worth of products, each year, although $328 billion of that sales volume is in fuel. If you aren't selling fuel, you will need to maintain a steady stream of customers purchasing at a healthy markup to remain in business. While most convenience stores require customers to walk in, creating a drive-through could be a healthy differentiator for you, and help you carve out a market niche, especially catering to parents with small children who are difficult to load and unload into cars.
Find a suitable location. Obviously, you will need a dedicated drive through window, at minimum, and ideally a drive-through driveway. If you can't purchase or lease a property already built with these specifications, you will have to build one. This means additional start-up costs. You will also need to get a permit for any neccessary construction.
Form a business entity. A business entity--either a corportation or a limited liability company-- helps to limit your own personal liability in the event of a judgment against your business. Otherwise, someone who slips on ice in the parking lot could sue you for damages and potentially take everything you own. To start an entity, file articles of incorporation or organization with the Secretary of State of New York. There is a $125 fee for filing articles of incorporation in New York as of 2011.
Obtain a business license. You will need to get this from your county government. There is a fee to get a business license. Additionally, you will have to collect sales tax and forward any sales tax you collect from customers to revenue officials.
Put insurance coverage in force. If you plan to hire employees, you must put workers compensation insurance in place according to New York state law. This coverage ensures there will be enough money available to care for any workers injured on the job, while protecting your business against shouldering the full liability for any claim. You will also want to explore obtaining liability coverage for the business, key person life and disability insurance coverage, disability insurance coverage for owners and managers, and business interruption insurance.
Purchase inventory. If you are purchasing a franchise from a convenience store chain, the franchise company may be willing to finance your inventory for you. You pay back the loan gradually as you sell product out of your store. There is an interest charge for this financing, but you may benefit from the franchise company's large scale purchasing agreements with vendors. You can also buy the inventory outright yourself, which saves on interest rates.