The value of your marbles depends on the condition of the marble and whether it was handmade or machine made, most machine made marbles from the US are worth only 10 cents. Other variables that determine what its worth are what country it was made in and how old it is. I have included a link below for you to check and see where your marbles may have come http://www.buymarbles.com/marbles101.html.
To find out the value of any antique, you'll have to contact a professional for an appraisal. Specialty websites like (http://www.collectiblemarbles.com) offers such appraisals. But if you wish to approximate the value of your marbles yourself, the easiest thing you can do is seach an auction site like eBay (http://www.ebay.com) to see what they're currently selling for.
To find the value of your marbles consulting with an appraisal is the only way to find the correct information. Marble age, condition, color and patterns makes the value of the marble. http://www.collectiblemarbles.com
Marble values, like any other items, are priced depending on the condition, design, and as for marbles, its size. Marbles, especially collectibles can cost 10$ and above depending on the appraisal. Things have varied worth from person to person so it depends on the appraiser to raise the worth of your marble. http://www.collectiblemarbles.com/ this site offers marble appraisal.
That depends on what type of marbles you have. The Christensen Agate Special marbles, with three and four-color flames sold at $18,400 at Morphy Auction in May 2008. If your marbles are more common, they won’t be valued nearly as high. Even though some marbles within the budget of average collectors, some could range into thousands of dollars.