I assume that the country you have never been out of is the United States. Clearly, you will need a passport or passport card.
Anything you don't have, you can buy in Canada, same brands, virtually the same prices.
Get Canadian currency from an ATM upon arrival, being sure to notify the number on the back of the ATM card in advance of your travel plans...the phrase I use on the call is "travel notification."
Also do a travel notification to your credit card company, and note that most US cards have a 3% fee for international purchases.