Make a second account at your bank. One account is 'storage' and has all your money. You never use the 'storage account' ATM card for anything outside your bank's ATM machines.
The second one is where you only keep $50-$100 in it. When you use your ATM card it's only this account that's used. Just before you make a purchase, move money from your 'storage account' into your 'active account' and make the purchase.
I second the idea of having a storage account. I do a similar thing myself but for other reasons. I always just keep $100 and every time I make a purchase I move money from my storage account over. The only problem is that this does not work as well with credit cards. I believe that in the US there is some form of company that allows you to make temporary cards for online purchases. Thanks ~ Bryce Wilson, AS202313