What’s a better deal: three-for-the-price-of-two or 70% off? This is not an IQ test but a demonstration of how tricky retailers can be when discounting their goods. Our colleagues of eZonomics wrote a piece some time ago that might come in handy.

A savvy financial approach is also useful in your daily shopping. Packed fruit and vegetables for €3 might be more expensive than what is sold one shelf above for €5. Comparing the price in large font on the tag is not enough – you need to read the fine print and compare the price per kilogram as retailers will use visual effects that could trick you into spending more than you budgeted. The same applies to canned or bottled items: a bigger, more expensive bottle might contain less than the smaller and cheaper one just next to it!

Colour can trick you too. In the UK, an Oxford University paper found that if men saw an advert where the prices were written in red, rather than black, they assumed they were getting a bargain. Women, however, become suspicious. “Men are less practiced shoppers (than women) and they see the red as a useful shortcut”, claims co-author Nancy Puccinelli. Smells and music are other tricks retailers will use to appeal more to customers, as you can read here.

Also in money matters, visual effects can lead to wrong conclusions. When studying fees or performance graphs make sure you compare comparable data. The performance of an investment asset during a short period of time can look quite scary (think of prices moving up and down due to speculation during an election week) and yet be a sensible investment in the long term (when looking at the performance graph over 3 or 5 years, maybe even longer). A credit card advertised with an initial cash gift might not pay off in the long run if the interest rate on credit amounts is higher than average. Remember that 1.17% per month is 14% per year!

Fool me once, shame on you. Fool me twice, shame on me! Don’t be the fool, be good at money and spend wisely your hard-earned income.