Jim Doolin issued a catalog on Columbian Admission and Concession tickets in 1981. It's out of print, incomplete (MANY concession and midway tickets are not included), and the pricing is horribly out of date, but it does have some great info like the quantity printed for each of the admission tickets. The Chicago Day Child's Ticket is the scarcest admission ticket of them all, with only 50,000 printed. For comparison, the four most common engraved ("non-A") tickets had a quantity printed of 1,000,000 each, The "A" versions: 500,000, Franklin: 245,000, Handel: 100,000. The other admission tickets sell pretty frequently on
ebay, so using the relative rarity differences, you could probably infer a value for the Chicago Day Child's ticket (and using that approach will get you in the ballpark IMO - I've collected this fair for >40 years).