Actually it is not difficult to buy a drone today. You can find so many retailers via online or in your neighborhood. Drones are available in different types, size, and definitely prices depending on what purpose you want to reach with a drone. Before you buy a drone several things need to know:
Number one is that not all drones are easy to fly. flying something needs great control and every drone flies a little bit different which depend on the flight controller setting. So from market we know that the easiest drones to fly are in range of $700. So, “the more expensive, the easier to fly” rule is true.
Number Two is that not all drones are ready to fly. For this you need to find acronyms such as RTF, BNF and ARF. RTF means Ready To Fly so you just need to do easier things such as charging up the battery, installing propellers or binding controller to quadcopter. Meanwhile, BNF means Bind And FLy. It is completely assembled but with no controller so you must use your recent controller (if compatible) or you buy a controller separately sold. The last, ARF stands for almost ready to fly. This drone has much similarity with quadcopter kits. You will not receive transmitter or receiver so you need to assembly it later.
Number Three is that you will find so many places to buy a drone. There are thousands online stores ready to send your order. The biggest among them are located in USA or China. My important suggestion is that you need to get warranty for product you buy and if you have more money you should buy drone in up to $700 range.
Number Four is my suggestion that it is good for you to be a member of drone community. You will have friends to share know-how or any issue related with drone and it is a normal for drone community members helping each other to find best place for getting drone.