Would you pay $99.99 for a wagon of Smurfberries?

If your answer is "yes," you might be one of the growing numbers of adults addicted to "Smurfs' Village," an interactive game featuring the little blue gnomes popularized in the 1970s and 1980s.

Or you might be a four-year-old playing on Mom's iPad.

The game, free to download and play, involves creating a Smurf village from scratch: building houses and planting and harvesting crops. For a fee, users can speed progress along with the help of "smurfberries."

A few weeks ago, parents of kids -- some as young as four -- were finding large sums of money charges to their iTunes accounts. Turns out, their savvy little land developers were going on a "smurfberries" spree, not realizing the coveted virtual currency costs actual money.

Many kids have fallen in love with the iPad or iPod Touch and parents, wanting to foster that love of technology, are quick to put the devices into their young ones' hands.

But a combination of apps with hidden charges, a loophole in iTunes' password policy, and inattentive parents can make for a pricy game playing experience.

The "Smurf's Village" app, offers "smurfberries" by the bucket, bushel, barrel, wheelbarrow, or wagon-full to users who want the ability to speed up the growth of their village and crops.

A single bucket is just $4.99. But a whole wagon-full is almost $100.

With a couple of quick screen taps, the charges are placed on the iTunes account associated with the iPod or iPad.

Normally, iTunes requires the user's password before any purchases are made. However, once the password is entered, it's not needed again for 15 minutes; not even to complete a pricey transaction.

This loophole is one children found immediately and many parents didn't until it was too late.

Capcom Interactive, Inc., the makers of "Smurfs' Village" are now warning consumers of the real-life charges associated with the game, most notably with a pop-up warning when the game is launched.

But there are plenty other apps for the iPod Touch or iPad that are free to download but have in-game purchase options that charge real money and have no pop-up warnings.

Some parents have balked at the the 15-minute password-free period loophole, but Capcom Interactive, Inc. and other app-makers say they have no control over that.

So what's a concerned parent to do? First, be wary of free apps. Since they're not charging anything to download the software, they're going to try to make money somehow.

Reading reviews on iTunes and online can be helpful, as some of the "upgrades" available are listed with how much they cost.

And while some free apps may offer the ability to disable these pricey "upgrades", it's probably safest to assume they can't be and gamers will have to play at their own risk. Even if they're barely in kindergarten.