You will not be charged any interest on purchases if you pay your entire balance by the due date each month. (smartasset.com)
If you pay off your balance a week before your credit card bill is due, then you will not be charged interest for what you have spent. (echeck.org)
In fact, you should really aim to pay off your TV purchase before the end of your credit card grace period to avoid being charged any interest at all. (badcredit.org)