I feel this blog post would be better if you just described what a spread is in a less roundabout way - but it's still very important people know about spreads (and I'm a bit jealous because I've been planning a similar blog post for a while!)

I feel like "No exchange fees" is trickey. I ask my friends where they think is cheapest to swap money, they all base it on the fees. "Best go to xxx because it's commission free". Currency exchange services blatantly are aware of this and are exploiting it pretty hard. I'm no expert, but that sounds like good starting conditions where different exchange services can charge a lot and don't really need to worry about competing with each other. I'm pretty sure average consumer ignorance and unwillingness to shop around beyond how much various services charge in commission is costing everyone dearly.

Spreads aren't limited to just banks either. Paypal used to be one of the worst offenders from what I recall, offering horrific profiteering spreads. To be fair to them though, nowadays they have improved.

Interestingly, Stripe advertises as "No hidden fees". I emailed them a while back and asked if they pass on the spreads they get from the bank to the user as I would consider it a hidden fee if they modified the spreads they were provided - I was pleasantly surprised by their response saying they would also consider it a hidden fee and offer the same spreads as they have access to. To me this was huge, and a massive hallmark of a company that's doing it right and treating their customers with respect.

Online poker also has been known to offer very expensive spreads when converting between currencies. Some of them felt very unfair and left a sour taste in your mouth - convert $100 to £80, then that £80 a second later back to $USD you would lose several percent of the original amount.

One of the worst and most expensive things you can buy are travelers cheques. Absolute rip off, I always avoid these. The security they offer you is the only plausible upside to them, which is a pretty marginal upside in my opinion. Post Office today is quoting £1 as $1.564, when the actual current market rate is $1.61358. They make 5c profit on every £1 you convert. Every £100 you convert, they chop of $5. That's only the first stage as well, if you have any left over be prepared to be raped when you want to swap them back.

When I travelled around the USA, I researched the best way to spend my GBP out there with the cheapest spreads as I was on a shoe string budget. Credit card won hands down. When I walked in the bank to get the credit card, I asked them if they offer market rate on the currency conversions. They said yes. When I got back, they had charged more than market rate on every transaction (I was expecting this). I complained and told them they lied to me, and got some free money. It's a good travel tip if you harbour general resentment for banks, that scenario will just keep re-enacting itself and is a cow you can keep milking if you can be bothered.

Best way to exchange cash is to meet up with a traveller coming in the opposite direction. Work out the market rate, swap the cash and be on your merry way. Possible startup idea?