Keep in mind that this is just my opinion...
Buy a couple dozen minnows and a minnow trap. As the others said, make sure that the bait shop fills the bags with O2. Also, buy a couple bags of Gulp artificial minnows.
On day 1 and/or 2 use your real minnows to locate the fish. Put your minnow trap in the water and try to catch some minnows out of the body of water that you are fishing. The shiny metal traps work better than the plastic ones. If it is ridiculously hot, you can keep your minnows in your trap, deep in the water where it's cool.
If/when you run out of live/real minnows, use the Gulp ones. Remember not to get any water on them until you are using them - this includes wet fingers reaching in the bag as they will start to break down. When done fishing for the day, take any of them off your hooks or they will be on there forever as they dry out and become rock hard.