US dollars are one of the world's most common denominations and are used in countless countries. You therefore might want to consider getting a dollar currency card instead of one in sterling.

We take a look at the advantages of a dollar prepaid card and how to find the best one for you.

The exchange rate

One of the biggest financial issues most travellers face is the exchange rate. Should you change all your holiday cash into dollars at the beginning and swallow commission charges or hold some back and hope that the exchange rate is OK if you need to change more at a later date?

A prepaid dollar debit card can stop the decision being such a gamble. By opting to have your cash already converted you don't need to worry about what to exchange and when.

When you top up your prepaid dollar card you lock in the exchange rate so not only do you know the exact value, you can also time your transaction to coincide with the market peaking.

In addition, one of the biggest problems that occurs when paying for transactions abroad is opting to have the purchase debited in sterling. Merchants usually are locked in to poor exchange rates which means that the bargain you thought you were nabbing will turn out to be more expensive than you expected. By using prepaid dollar cards instead, you will pay the same price that you saw on the shelf.

Of course, what you should bear in mind is that not all prepaid dollar debit cards offer the same exchange rates. The cards dollar exchange rate will vary between providers and the difference can be very significant. The good news is that the best exchange rate on prepaid dollar travel cards will be better than you would get than if you were using cash. If you compare cards you will get an idea of the rates on offer - although these will of course fluctuate as the market moves up and down.

Transaction fees

But if you are carrying out a prepaid dollar card comparison, the exchange rate isn't the only factor which could influence how much money you have to spend.

Credit cards are notorious for levying transaction charges as well as slapping on a huge fee if you want to use an ATM. Pay as you go dollar travel cards will normally work out much cheaper, but some providers are better than others in this respect.

The best prepaid card for dollars won't charge you extra for overseas transactions nor withdrawing money from ATMs so it's worth comparing different cards before applying. However, other charges (see below) could be more expensive so you need to weigh up which option is likely to work out cheaper. Unfortunately, there's not one specific dollar cash card that can be singled out as being the market leader as finding the best value for money will depend on your individual spending patterns and circumstances.

Loading costs and other charges

Unfortunately, the best prepaid dollar travel card providers in relation to ATM and transaction fees often levy other charges which you need to consider.

Some prepaid dollar cash cards attract a fee every time you top up your balance. This can either be a percentage of the value or a flat fee, typically between 1-3. If you top up your account regularly with smaller sums, what started out as a card for cheap dollars can end up working out quite expensive. Conversely, if you only load up occasionally with a larger sum, picking a provider which charges a flat fee and no ATM or transaction charges might work out more cost-effective.

However, loading fees aren't the only other charges you need to check for when comparing prepaid dollar credit cards.

Some providers charge a monthly management fee, others require you to pay a sum - usually around 9.95 - on application whilst quite a few also start to deduct charges if your card is inactive for a number of consecutive months.

In order to find the best deal, you will need to work out how often and in what way you plan on using the card, and then find a provider offering the lowest charges for these facilities.

Finally, if you are travelling elsewhere in the world, it's worth knowing that when it comes to a prepaid currency card dollars are not the only denomination you can choose. Sterling, euros or even more exotic currencies such as the South African rand can be found from different providers.