Companies may be looking to social media as a cheap alternative to traditional advertising, but it certainly isn’t free. It takes time, effort, and often — money. Witness today’s trending topics on Twitter.

Michael Jackson’s stronghold on the most popular topic all week has finally been loosened by a much more frivolous word: Moonfruit.

Entirely unrelated to the Moon Walk, Moonfruit is a DIY website builder that is giving away 10 free laptops to celebrate its 10th anniversary. All people have to do to qualify is advertise the company on Twitter with the hashtag #moonfruit. The campaign is certainly working. But is it worth $12,000 to be the most popular Twitter topic?

Moonfruit isn’t the first company to trade free stuff for brand recognition and a longer followers list on Twitter. Most recently, SquareSpace (another DIY site builder) offered to give away an iPhone a day for the month of June to people who tweeted the hashtag #squarespace.

Moonfruit has adeptly avoided some of the pitfalls that befell SquareSpace. SquareSpace announced their giveaway as an appreciation event. Their website called the contest a “gigantic THANK YOU to all of our favorite Squarespace fans,” even though it was clearly a marketing campaign to boost the brand on Twitter.

Another small snag was the prize. Instead of new iPhones, SquareSpace was actually auctioning off $199 gift certificates to the Apple Store. And unless you are eligible for a new AT&T contract, that’s a lot less exciting prize (an unsubsidized iPhone runs as much as $699).

But SquareSpace was trading on the popularity the new iPhone garnered in June. A contest with a $199 prize would not have faired nearly well. And despite charges of deceptive advertising, Twitter users today are still happily retweeting the SquareSpace name (even though the contest ended in June).

Moonfruit has a better chance of winning people over with customer service. For starters, a MacBook is an even more expensive prize. And the company has promised to order, purchase, and ship complete laptops to the 10 lucky winners.

But the cheapest MacBook is priced at $1,199. Meaning that Moonfruit is spending $12,000 to get some attention on Twitter. Meanwhile, SquareSpace spent a sum total of $6,000 on Apple gift certificates.

If Moonfruit’s adjustments to their contest boost consumer satisfaction, and consumers choose them over SquareSpace when they need to make new websites, the more expensive prize could be worth the outlay.

But it still remains to be seen if any of the people Twittering about this will become customers. Or even continue to follow either company on Twitter for long after the contests end.

Either way, contests that aim to top Twitter’s trending topics list are certainly blurring the line between earned media and paid media.