The value of the pound reached 31-year lows last night, after a 'flash crash' meant it was at one point worth just $1.18. It's since recovered slightly, but many due to go on holiday will now be wondering about their purchasing power abroad.

While you can't do anything about the exchange rates themselves, there are still ways to be sure you make the most of your money when buying foreign currency or spending abroad:

  • The 'buy cash' trick to protect against currency swings. While they may not offer the very best rates on the market, a few bureaux's terms and conditions can be manipulated to give you protection against currency swings for up to 30 days, as you get the rate on the date you order for collection before your holiday.

    That way if the rate gets worse, you're up as you got it at the rate on the day you ordered. If the rate gets better, you cancel penalty-free and then buy at the new rate.

    Bureaux offering this service include Travelex, Tesco, Sainsbury's and Moneycorp – though in all cases there's a limit to how far in advance you can purchase your currency. Travelex is currently the most flexible, letting you order up to 30 days ahead, yet cancel free of charge up to 24 hours before you set off.

    We've checked the terms and conditions of these cancellation services this afternoon and they appear to be unchanged. But it's worth noting previously we've seen terms change after big currency swings, so double-check before buying. See the Buy cash trick for full info and what to watch out for.
  • Find the best rates from 30 bureaux with the TravelMoneyMax site and apps. Our TravelMoneyMax (TMM) travel money comparison tool compares rates at about 30 online bureaux and orders them by how much currency you'll actually get after all fees and charges.

    We now also have the TMM iPhone app or TMM Android app, which do the comparison too. They've the added function of a personalised currency calculator – it stores what plastic you have and what you paid for your holiday cash. Then when you go to buy something it shows YOUR cheapest way (ie, which card or cash).
  • Get near-perfect rates everywhere, every time with a specialist overseas credit card. Some cards don't add a sterling exchange fee, so you get near-perfect rates when you spend abroad – though make sure you repay in full.

    These include the Creation Everyday and Halifax Clarity, or if you withdraw a lot of cash, the Barclaycard Platinum Visa may win, as it has no exchange fee until 31 August 2018. Also, unusually it doesn't charge a cash withdrawal fee or interest on overseas (not UK) withdrawals if you pay your bill in full. See Top Travel Credit Cards for full info on all these cards and how to apply.
  • Get a Supercard. Anyone can get the Travelex Supercard because there's no credit check (though there is an ID check), but you do need a smartphone to use it – it's all done via app.

    It lets you link existing debit and credit cards to it (except Amex), then you spend on it and it charges your existing card in pounds (you choose which card in the app), having done the conversion at the near-perfect Mastercard wholesale rate.

    The rate is far better than you'd get spending directly on most cards and it means if your linked card gives you cashback or rewards, you still earn them. However, cash withdrawals overseas have a 2.99% fee (more expensive than the cheapest specialist credit cards) so it's best to spend on it where possible, rather than withdrawing cash. For more, see Supercard analysis.

For more options and help, including the best prepaid cards and why you should never change cash at the airport, see our 17 Cheapest Ways To Get Travel Money guide.