The Texas State Fair that opened today has all sorts of promotion days to where you don't have to pay $15 to get in. I know on Tuesdays if you bring a Dr Pepper container/can you can get in for something like $4, on Wed Kroger is working with the Food Bank and if you bring in 3 canned goods the price is $3, also after 5pm the Dr Pepper can thing gets you in for $5 on I believe any day. Also Coca Cola has a promotion going where they have reduced ticket price coupons at Mc Donalds and they also have something with a 20oz unoppened bottle of Coke that gets you in a a lower price. Even Dickies clothing has a day where you can get in FREE if you wear their clothing line, heard something if you dress as Big Tex with the yellow shirt and Dickies Jeans you get in free on that day. (looked all over Dickies site and could not find the promo there nor even Big Tex's shirt for sale on line) Found out it is Sept 30th not sure if you have to wear Dickies Jeans and the Yellow Shirt (which they are selling on the Fair Grounds for like $40) or not. If your 60+ it's free admission on Thursdays.
I've found Tuesdays the last couple years as being a decent day to shoot photos-not too crowded but enough people to make things look busy and if the weather is bad you can then plan on Wed and still get a shoot in that week.
Also don't forget that a lot of school districts across the state still have fair days so you usually have plenty of kids around on any given weekday.
Alas Parking in State Fair lots now is $15 up from $10 so if your a small group you may want to consider arriving by Rail- shouldn't be too bad after morning rush hour.
DART.org - Ride DART to the State Fair of Texas
So if people want to meet up on a Tuesday morning or a Wednesday post it here.