As the other person stated, a picture would be helpful. However, given the rating you describe, I would guess it is a ceramic capacitor of the non-polarized type. Voltage rating does not matter. A place that services or installs electronic equipment will have them. Also, find a local ham club. Almost surely they have a member that will have what you want and give it to you for free. Such capacitors are really inexpensive.
That brings me to another thing. If you look at all the parts in those kits, most of them can be bought for pennies. If you do buy the capacitor on line, consider buying other parts too and thus expanding what you can do. A "Solderless breadboard" is the way to connect such parts without the set up in that kit.