All these "free" domain offers seem to suffer from the same problem - they make their money from you at the end of the 1st year by hanging on to your domain until you pay up for the 2nd year (with higher than average fees).
There are currently at least 2 offers for free TLDs mentioned here on x10 ;
http://forums.x10hosting.com/news-announcements/61963-free-domain-read.html
http://forums.x10hosting.com/ads-offers/85043-free-co-uk-domain.html
I have tested both offers (& registered domains for other members) & believe them to be still valid, though I think the GoDaddy offer you mention has expired.
Just how easy it is to transfer to another, cheaper registrar at the end of the 1st year remains to be seen, because many of the offers haven't been around long enough to find out yet, & because x10 members have given little or no feedback to any problems they have encountered once they registered.
My preference would be to only go for TLDs (.com or .co.uk etc) now the free .co.cc domain offer involves a renewal fee & is therefore no better than the other offers. But you may have to treat the "free" domain as disposable after 1 year - unless you plan to pay their high fees after that.
If you want to own the domain long-term you may be better off ignoring the "free" offers, & choosing your registrar based on their service & prices, & paying for it from the start. After all, you do tend to get what you pay for!
... is there any option to get atld forever(not for free, bt at a reasonable cost)?
Not forever, but most registrars allow you to register for multiple years, such as 1,2 or 5 years. The maximum time you can register may depend on whether it is a .com, or .co.uk etc. The longer you register, the cheaper it gets (but you have to trust the registrar will still be in business several years down the road

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