Perhaps you still have an old fashioned TV and see no reason why you should purchase a new one. As long as you are using cable, you should have no problem.
But if you use an antenna, your TV is probably useless now that over-the-air transmissions are now digital. You require a digital converter box to convert the digital signals into analog signals.
You can purchase those digital boxes for around $50. But if you do, then you should perhaps consider the HomeWorx HW-150PVR ATSC Digital TV Converter Box.