You may have seen recent adverts offering a free PC in return for signing a mobile broadband contract.

Is the laptop heading the way of the mobile phone - destined to become a cost-free incentive for those willing to commit to lengthy broadband subscriptions? And are the "free" deals really as attractive as they first appear?

Here, we're going to investigate the free-laptop phenomenon: how the companies behind the deals make their money, how much you pay for that "free" PC, and how to navigate the different deals available from retailers.

We've also reviewed the "free" laptops available, to reveal what kind of quality hardware you can expect for your modest monthly fee.

Flattering to deceive?
Free laptop deals may be popular - but you're still paying for the hardware, it's just disguised in a digestible monthly fee that's spread over 18-24 months. Although the Australian offerings thus far are good value, in some cases, you may end up paying more over the full term of the contract than you would if you bought the laptop and mobile-broadband connection separately. The key is to do your sums carefully.

Vodafone's widely promoted Dell Inspiron + mobile broadband provides a Dell Inspiron mini 9 together with a two-year, $59.95-per-month 5GB contract on Vodafone, giving a TCO of $1439. The same 5GB broadband tariff was $39.95 direct from Vodafone, which when added to the $600 cost of the laptop comes out just less than $1558. That's a $100 saving for buying both together.

At the time of publication, Dodo was offering a free Asus Eee PC 701 on a $59.90-a-month, 2-year contract - giving you a total cost of $1430.40 by the end of the contract. To buy the laptop ($300 from Officeworks), Mobile phone ($249 from Dodo), mobile plan ($29.90 per month from Dodo) and mobile broadband (between $10 and $20 per month from Dodo) (plus mobile dongle?) separately would cost $1746, so by opting for the combined deal you'd save around $300.

Free for all
The "free laptop" isn't necessarily the bargain it may first appear. Although there are good deals to be had, many work out more expensive than buying the laptop and broadband separately.

Models offered in free laptop deals are low-powered netbooks; as you'll see from our reviews, the majority of these laptops will suffice for basic surfing and lightweight tasks, but cutting-edge components are a rarity.

For those who are planning to sign up for a new mobile or fixed-line broadband connection, the bundled laptop might be a worthwhile bonus. Those who think they're going to save themselves a packet on a new PC may discover that they're paying more in the long term than they originally intended.

Verdict
Prepare for a shock: "free laptop" deals aren't always quite as astounding as they might first appear. Work out how much a plan costs over a 24-month period, while making sure to factor in any initial or additional charges, and you'll soon realise that many deals have a sting in the tail.

We've been expecting for some time that mobile broadband deals will see increasing speed and bandwidth over the next 6-12 months, so check whether you can increase your download limits, and also check whether the quota will increase if other offerings from the provider increase. For example, Dodo only allows you to move to higher value plans within its 24 month contract terms.

That's not to say there aren't some good deals to be had elsewhere. Neither the Eee PC nor Dell's Inspiron Mini 9 can lay claim to being the undisputed netbook of choice - but as the only two models here to boast integrated 3G, and with both costing little more than it would to buy the laptop and a separate 3G tariff, they're actually pretty good value for money. Then again, if you really want the best netbook going and aren't phased by the loss of integrated 3G, the likes of the HP Mini 1001TU prove remarkably affordable.