For the table service restaurants you can go to the dining reservation page for the specific restaurant you're interested in. It will list the times for the various meals, but it can vary somewhat depending on the season. If you're within 180 days of your visit you can input your specific date to see the schedule.
As far as lunch being cheaper than dinner, there are some restaurants with the same menu all day long, such as Via Nap, Sci Fi, '50s Prime Time, Mama Melrose, Yak & Yeti, so the prices will also stay the same.
You can check menus on allears.