The European Consumer Centre in Ireland is issuing tips for buying goods online today and on Monday.
Today, known as Black Friday after Thanksgiving in the US, is regarded as one of the biggest shopping days of the year. It gives consumers a chance to purchase some items at cheaper prices.
It is also popular across parts of Europe, with many retailers offering a variety of discounts and deals over Black Friday and Cyber Monday.
Up to €74m is expected to be spent in Irish stores over the so-called "Black Friday" weekend.
Last year, Irish consumers spent an estimated €39m on Cyber Monday alone. Online sales are expected to grow by around 5% over the festive period.
Press officer with the European Consumer Centre Grace Duffy said: "Consumers should read any terms and conditions that might be attached and make sure the trader provides information on cancellation policies, delivery times and any taxes and charges that may be involved."