$4 for adults, $2 for kids under 2 is free. Perfect. This Zoo is non-commercial, you can see all of it in under 2 hours. You can get VERY close to several of the animals. Made for a wonderful family outing today. Rent a wagon for $2 or a stroller for $1. Parking is free. Beats the Topeka Zoo by 10 times in all aspects. 

I agree that its a great value. I've seen many people bad mouth it and I think they are just spoiled. I've been to zoo's all over the country and while yes, its tiny, its also cheap. My kids have never complained when we go there. Too often when we go to Topeka we skip the zoo and just enjoy the rest of the park it sits in instead. 

You should consider getting a year long zoo membership.
If you are military it's $45.00 for the year or $50.00 if you aren't military. If you have two adults and one child and visit the zoo 5 times during the year it has paid for itself, but with membership you also get free or 1/2 price admission to many zoos throughout the country as well. The membership is good for 2 adults and all children under the age of 18 living in the household. Most reciprocating zoos allow free or 1/2 price admission for 2 adults and 2-3 children. We join every year and get our moneys worth easily as there are 5 of us. If we visit just three times it has just about paid for itself. Not to mention that we use the 1/2 off at Omaha and MN zoo's at least once a year as well. You can see a list of reciprocating zoos on their website.
We love our zoo membership.