Any Good Channel to Get a Used Bike?

There's always Craigslist. And depending on where you are, there's a site called napervilleyardsales.com that frequently has gently used toys and other childrens items for sale. Both sites allow you to post "wanted" ads where you can tell people exactly what you're looking for and how much you're willing to pay.

Another site that's around you might want to look into is freecycle.org. You can register for different chapters according to where you live and are willing to travel to for pickup purposes. Items like bikes may be harder to find there, but you may get lucky and find someone who just wants to be rid of whatever it is you ask for.

Good luck!

You could try "Play it Again Sports." They have a multiple stores in the area, including one in Naperville. They also have a website you can google.

Check out napervilleyardsales.com

It's like ebay, but everyone is local!!