Last week I finally figured out why I had some problems using the Discover Debit card in the past. My problems typically occurred when I purchased gasoline at the Sam’s Club gas station and then went in to purchase my groceries. Little did I know that “they” put a $100 hold on my account in addition to my gasoline purchase. So my available balance would be down $100 for three days. I guess I should see what other debit cards do.