I purchased a Marine Metal Aerator Bubble Box 1.5V on Amazon for $8.99. Two D cell batteries last for 2 days and it keeps most of 2 to 3 scoops of minnows alive in a 5-gallon bucket (1/2 full). I pull the dead ones out and try to keep the water from getting too warm (bucket in shade and change out 1/3 of the water every couple of hours).
Sandusky Bait (city ramp) has the most consistent stock of shiners or goldies imo. Unfortunately my experience with Pipe Creek is that they were always out of shiners but, per your post, they must be closed now...