There is an increasing number of websites that are offering 'free' ads - but are they? They may well be free to post, but as soon as you connect to the advertiser, you could be in for a shock when you check your next telephone bill.

An increasing number of 'free ad' websites are using numbers starting with 070 that are listed on each posted ad. These numbers are classified as 'personal' numbers and can cost a small fortune, should you be talking to the advertiser, which is often the case. There may well be a connection charge, and call rates are uncapped, some can reach as high as £1.50 per minute. And there is rarely a warning message to tell you the call rate as with many 090 numbers. 070 numbers should not be confused with mobile numbers that also start with 07. If you need to clarify further, call the UK regulator, OFCOM on 0300 123 3333 or 020 7981 3040 or visit their website http://www.ofcom.org.uk/contact-us. They are open Monday to Friday from 9.00am to 5.00pm.

Alternatively enter "070 numbers" into your search engine.