First, they learn to share. Then they start to swap (hence the ever-changing stash of Hot Wheels in your playroom).

When they’re ready to wheel and deal, there’s Sugarcup Trading. Oak Park’s just-opened kids’ boutique sells new merch for ages newborn to tween, and also takes items you’ve fallen out of love with off your hands in exchange for credits that can be applied to purchases.

A few rules: You can trade in only what’s on the store’s current wish list — typically high-demand toys like American Girl dolls and Legos, and brand-name clothing such as Abercrombie & Fitch and Gap. Each trade-in earns you points; accumulate and spend them on the store’s selection of new and traded goods. (Each item for sale has a tag with both cash price and point value.)

Finding a treasure isn’t tough. The rustic-looking space is a trove of organic-leaning goods like Kicky Pants apparel, Lunchskins bags, ErgoPouch swaddles, and Ecojot notebooks.

Look for swap nights, when kids can trade hot items (hello, Silly Bandz) freely with their peers. Savvy little buggers, aren’t they?

Sugarcup Trading, 110 North Marion Street, between North Boulevard and Lake St., Oak Park (708-524-5336 or sugarcuptrading.com). Prices for new goods range $40-$150; traded goods range $10-$50.

WELCOME
Monnalisa and L.O.L. Kids
What: The side-by-side kids’ clothing shops opened in the Gold Coast. At Monnalisa, luxury Italian threads. At L.O.L., designers like Sonia Rykiel and Roberto Cavalli.
Why: Dressy holiday parties are ahead.
When: Mon.-Sat., 10 a.m.-6 p.m.; Sun., noon-5 p.m.
Where: 49 E. Oak St., at Rush St. (312-929-2229).

SEE
The ComedySportz Crew Meets Snow White
What: The partly improvised show based on the fairy tale vies to be the fairest of them all.
Why: Kids are invited to make sound effects and act on stage.
When: Thru Jan. 29. Sat., 11 a.m.
Where: The ComedySportz Theatre, 929 W. Belmont Ave., at Wilton Ave. Tickets at 773-549-8080 or online (adults only) at ticketmaster.com. Adults, $10; kids, $7.

CELEBRATE
Birthdays at Family Grounds Cafe
What: The coffeehouse/play space can now be rented for private or semiprivate fetes.
Why: No cleanup. Duh.
When: It’s time to put another candle in the cake.
Where: 3652 N. Lincoln Ave., at Patterson Ave. (773-281-0785). Private parties start at $450; semiprivate parties, $30 plus $6/guest.

Photo: Courtesy of Sugarcup Trading