Always a good idea to gauge the charges well in advance. Without a roaming or domestic text plan or add-on, any incoming and outgoing calls while in US will be billed at $1.45 per minute. It's 75¢ per Sent Text/Picture Message and 25¢ per Received Text/Picture Message. Pay per use data charges are $7.99 per 50MB.
Depending on your plan, you may be automatically enrolled in Roam Like Home. With RLH you'll be billed $6 per day for a maximum for $60 within a billing cycle to use your plan how you do in Canada.