What do I need to send and recieve data

I'm about to purchase a bunch of stuff but I need to know what additional stuff I need to get. The main goal is to simply send data to the arduino from c# and receive data from the arduino in the same c# program. If I buy the Arduino mega, what other components will I need? I have looked on the internet but haven't found a clear definitive answer. I don't know if I need some serial to usb adapter or if the arduino somehow tells my computer the usb port can be used as a com port.

Thanks

You don't require anything additional to the Arduino board. Part of the Arduino software installation is installing the FTDI USB serial comm driver. Once this is loaded your PC system will show a new additional comm channel (mine shows up as com4) anytime the Arduino is plugged into the PC.

So any PC application programming language that can talk to PC comm ports will have a path to send and receive serial data from a attached Arduino board.

Lefty