Little Amerricka in Marshall, Wisconsin (near Madison) is an excellent small town amusement park. There's no admission fee, no parking fee and you can buy ride tickets or wristbands. We ended up buying two gold wristbands for my son and I, which worked out great. He loves mini golf and that wristband includes unlimited mini golf.
Since I only had one 8 year old with me, we didn't check out the little kid ride area, but it appeared that they had many fun rides for little kids. The variety of rides there is really nice because there's something for everyone and all ages can enjoy amusement park. We arrived at opening time and were able to park so close that we could easily walk back and forth to the car for drinks and snacks.