Although both the USA and Canada have Dollars and cents and the same denominations of coins, the designs of both banknotes and coins are different in the two different countries - banknotes are very different, coins only slightly different.
American banknotes all have the same basic design, so you need to check the denomination very carefully when handling them. Canadian banknotes have very different designs for different denominations.
In the USA $1 coins (Silver Dollars) are rare except in Las Vegas.
In Canada both $1 and $2 coins are in common usage. The Canadian $2 coin is made from two different metals - it is silver-coloured on the outside and gold-coloured on the inside.
The Canadian 1c (penny) coin has numerous straight edges, whereas the American 1c (penny) coin is round.
Coins:
A "buck" is a Dollar; two bucks is two Dollars, etc.
The expression "two bits" has two meanings - either 25c or virtually worthless.
Coins:
In both the USA and Canada travellers' cheques in the appropriate currency for each country are treated as cash in most retail outlets such as shops, restaurants, petrol stations, motels, etc., with reasonable amounts of change being given without any problems. No commission charge is ever made. Most motels are also quite happy to cash traveller's cheques for you, both when paying and also separately to payment for your accommodation. Occasionally some form of identification is required when cashing a traveller's cheque, for which your passport or driving licence is ideal. Some fast food restaurants will take traveller's cheques, some won't. Non-fast-food restaurants normally will take them.
There would be a commission charge for changing a traveller's cheque in a bank, so that option is best ignored.
To avoid establishments having to give you large amounts of change and also to avoid you having to carry large sums of cash, we feel that it's best to get $50 travellers' cheques.
It is difficult to give any specific advice as to the cheapest sources of travellers' cheques and US cash in this document since the market is very changeable. The best bet is to shop round the travel agents, banks and building societies, not forgetting (at least in Britain) the Post Office. Consider both the rate of exchange and the commission charge.
It's a good idea to take a debit or credit card and know your PIN number so that you can use an ATM (automatic teller machine - i.e. a cash dispenser) in an emergency, although the commission charges for obtaining cash from ATM's are high. Using a debit card to obtain cash from an ATM is considerably cheaper than a credit card. If you intend to use a card to obtain cash, check which network your card can be used on, for example the Plus system. ATM's are widely available in the USA, slightly less so in Canada.