since i live in houston, i guess i can help ya out. i go every year, usually for 10-15 of the 19 days. i get an exhibitors badge so i dont have to pay, but i can tell ya about the fees. to go to the rodeo every evening at 7:00pm (except weekends, which are at 3:00pm), you must buy tickets in advance through ticketmaster. if i remember correctly tickets start at $17 and go up to $72. may sound expensive, but thats great considering you get 4 hours of entertainment, you also get into the livestock show free with a rodeo ticket. if you do not plan on going to the rodeo, you can buy tickets to the livestock show when you walk up to the gates for about $6-7. also both of those get you into the carnival, but rides cost extra money (way too much if you ask me). the carnival in my opinion is a waste of time, but brings a lot of visitors, it does have good food though.
the livestock show has everything you could want to see, if your there on the right days. obviously they cant cram everything in at the same time, so some days they have bulls, some days heifers, steers, goats, etc all spaced out through those 3 weeks. best bet is to check
http://www.hlsr.com later on closer to show time to plan when you wanna visit. also, if your interested in Brahmans, the international brahman show is held at the livestock show. President Bush made a special visit to the brahman show last time around, hopefully he will again next year when im showing there.
hope that helps you, if you have any questions at all ask away.