Most of us now regularly download music from the internet to play on our PC or to transfer to our digital music player. But how much we pay and what we get for our money can vary, depending on which of the 50 legal sites we choose.

Apple, for instance, is cutting the cost of its iTunes music downloads after accusations that its pricing disadvantages British consumers.

The entertainment giant will cut the price of UK downloads – which cost 79p compared with 74p in the rest of Europe – within six months, after pressure from Which?, the consumer group.

An investigation by the group found that Britons were forced to pay more than their European counterparts for the same music because the company barred them from shopping at the cheaper iTunes services based in France or Germany.

As well as a range of prices, digital music files come in a variety of formats. So you must check that you can download your tracks in a format that is compatible with what you intend to play them on. MP3 files work on most devices, including iPods, but Windows Media Audio (WMA) files are less widely playable.

Digital rights management (DRM) is also worth checking. This manages what you can do with a music file, such as how many times you can copy it either to a CD or another machine, such as an MP3 player.

Rob Barnes, head of broadband at moneysupermarket.com, the price comparison website, says that the success of the iPod has meant iTunes is probably the most well known and trusted site. But until the new pricing comes into effect, each track will continue to cost 79p to download. Most albums cost £7.99.

DRM-free songs (there are no limitations on the type of music player or number of computers you can play them on) were introduced last April with iTunes Plus. If you are already a member of iTunes, you can upgrade your collection for 20p per song or 25 per cent of the album price, and then download them to a device other than an iPod. But only EMI’s digital catalogue – which includes Coldplay, the Rolling Stones and Lily Allen – is available at present, but other artists will be added later.

Mr Barnes says that other providers offer downloading services for the same price or less. Single downloads from hmvdigital.com, for example, can be 20p cheaper than iTunes; albums are £4 less.

Napster.co.uk, which offers subscription services as well as pay-per-track, is iTunes’ best-known rival. Tracks cost 79p on Napster Light, a pay-per-listen service, and albums from £7.95. The songs are yours to keep and you can transfer them to more than 75 compatible MP3 players.

Alternatively, Napster Membership costs £9.99 a month and gives you access to Napster’s catalogue of four million tracks to play on your PC. If you want to transfer the tracks on to another device, such as an MP3 player, you will need Napster-To-Go, which costs £14.95 a month.

You must keep paying the subscription for Napster Membership or Napster-To-Go, or you will lose access to the songs. If you want to keep them for good, you pay 79p a track or sign up for multiple songs with a Napster Track Pack, bringing the price down to 68p.

Peter Ruppert, founder of Entertainment Media Research, says eMusic.com is probably the cheapest site at £8.99 for 30 downloads – or about 30p for each track.

“The disadvantage is that it is a subscription service and they have a limited repertoire,” he says. “They won’t let you browse before agreeing to a trial subscription, so there is a bit of an anticlimax.

“Don’t expect too many major hits, but an indie fan could probably be happy here. The advantage is that they deliver tracks in MP3 format without DRM.”

Meanwhile, Tescodownloads.com charges 79p a track, Wippit.com anything from 29p to 75p a song, Easy-music.com between 25p and 95p, and Woolworths.co.uk 59p to 79p. Album prices vary from site to site and by artist – current chart toppers are more expensive.

A number of illegal “peer-to-peer” sites allow users to share their music collections free with other members. But Manoj Salonki, of seekbroadband. com, is wary of these sites. “Their content may be seemingly unlimited, and technically free, but you could be opening up your PC to security threats, such as viruses,” he says.

“There are also privacy concerns – cyber-criminals are increasingly using peer-to-peer networks in identity theft. Legitimate music sites, with fully licensed content from the record labels and artists, guarantee a safe way to download music legally.”

Beware, too, of sites that claim to offer free downloads. Some display songs by well-known artists but the small print shows that they are often performed by unknown groups. Others give away music from unsigned bands, so don’t expect to find your favourite artists.

Broadband is a must, as tracks can take several minutes to download on dial-up. And if you plan to spend hours boosting your music collection, check that you are on the right broadband package.

“A 1Gb-a-month limit will very quickly get eaten up after accessing some new playlists,” says Mr Barnes. “Even if you have unlimited downloads, extreme users may be hit with hidden charges for going outside their fair use policy.”

If you want to bypass your PC and download music straight to your mobile phone, the options depend on the network you are on and which handset you have.

Vodafone MusicStation and Nokia Music Store both launched on November 1 last year. For £1.99 a week, Vodafone customers can now download unlimited tracks from Universal Music Group, Sony BMG Music Entertainment, EMI Music and Warner Music Group direct to their handsets.

The Nokia Music Store can be accessed via a compatible Nokia handset, or a PC. Individual tracks cost 80p and albums start from £8. The store also offers a monthly £8 subscription for PC streaming– which allows you to listen to tunes online without downloading them.

Since July, T-Mobile has offered more than one million tracks at £1 a song on its Mobile Jukebox. It offers a dual-download service to both compatible handsets and PCs.

Rival network 3 has a similar service with 3MusicStore, which offers 1.2 million tracks at £1.29 each.

CASE STUDY: Making it official

Rose Price, a freelance editor from Chester, regularly uses iTunes to download music.

She says: “I chose iTunes because I have an iPod and it makes sense to go to its official downloading site. I also thought it would have greater security than some of the other sites. My main concern is security – as I didn’t want downloading music to make my PC more vulnerable to viruses.”

Miss Price, 55, mainly saves the music on to her iPod but also burns CDs to play in the car. However, she has found it difficult to download tracks she has bought on iTunes on to other media.

“They won't play on my home stereo system or on other types of MP3 player. You can feel like you have bought the song but you don't actually own it,” she says. “But the good thing is that iTunes has a lot of choice and you can download single tracks from different albums.

“I used to buy albums and only really listen to three or four songs on each one but now I just buy individual tracks and have ended up with quite an eclectic mix, including Aqualung and Sigur Rós. I download about a dozen each month but have probably only downloaded two complete albums.

“At 79p a song I think it’s really good value. What else can you get for under £1 these days?”