The Nokia 5800 is the first real mass-market smartphone that also doubles up as a great music player, so teaming it with Comes With Music is a fantastic idea.

What's more, you can now get it exclusively from Orange for free, on contract for just £25 a month. We think that’s a bargain and we’ve done the maths to work out exactly why.

The Nokia 5800 costs £299 SIM free but you can get it from Orange for nothing if you sign up to one of five specially created price plans – the cheapest of which is just £25 a month, the most expensive just £44.04. Orange customers can also download tracks ‘Over The Air’ using the Nokia 5800 at standard mobile data rates.

Comes With Music started life as being a one-year subscription deal but we think the clincher with the Nokia 5800 from Orange is that you can carry on downloading music for free for the full 24 month term of the contract. Naturally, you can carry on subscribing after this period but we thought we’d look at how many albums that pans out to in two years.

Individual tracks on Nokia Music, for example, cost 80p each, so without Come With Music, you’d be paying £8 for a 10 track album, which is roughly the same as 31 tracks or just over three albums a month to match the cost of a £25 a month contract.

Then there is the fact you can download as much as you like on Comes With Music and no one is ever going to take it off you! So, £25 a month works out at two £10 CDs a month and two CD singles, which isn’t a great deal when you think the average Comes With Music user downloads over 30 albums in the first few weeks alone.

Don’t forget, Comes With Music can share music on your Nokia 5800 as well as one PC in the house, so you don’t have to limit it to building a music collection just for yourself. For instance we’ve set it up on the family netbook and downloaded 50 albums in the first week!

If you only download 10 albums a month, or 100 tracks that comes to £80 if you bought them online – so you’re saving £55 a month simply by using Comes With Music.

Now, if you follow the standard user trend and download 30 full albums (worth £240), suddenly you’ve saved yourself £215 in the first month alone - so, is the Nokia 5800 Comes With Music worth £25 a month? The numbers certainly think so and who can argue with maths?