I am now recovering after an exhausting day with two young girls. I am not the parent, but was the backup adult. It was a nice day so we went for a long walk and the goal at the end was the aquarium. The aquarium is awesome but at $30 per adult and $15 per child, it is a bit pricey. There is no question that the kids loved it and that this was probably one of their more educational outings as they live in a small town that doesn't have facilities like this. I am wondering about other ideas for children in this age bracket (9 & 11 currently). We have other facilities here in the city, but they all run a similar price. What can I do to keep them occupied for a day that isn't going to break the bank?
The city you're in would really help with suggestions but if that's something you're not comfortable with I would suggest nature. Biking is a fun thing for everyone. Or rollerblading. Or some kind of sport. Parks are fun with activities. You can go out and forage for edibles if weather is permitting in your area.
The only thing that i can think of is to take them to see a movie. For 1 adult, and 2 children the price should be under $20. Your are not going to find any other activities cheaper than that.
I love to hiking with the kids out in nature. There isn't a lot of places to go hiking in the area I am not but there are a couple of places. The hiking places back in Idaho were never ending. We found a lot of excellent hiking sites there, but not so much in Texas unfortunately.