I met a guy before the turn of the century that lost over $40,000 with his debit card. I would not have one but if you have no other choice then I suggest that you tie that card to a special account with a relatively small balance. What ever amount you think you can stand to lose whether that be $500 or $5,000 that is the amount you should put in that account. If you need to make a larger purchase then put those funds into the account shortly before your purchase.
It is probably not a good idea to put all your money into one institution or even one type of institution. Remember several years ago when the savings and loans were shut down and none of the money in them was accessible for many months.
Another thing to think about is that if you use a debit card you can use cash just as easily. This has an added benefit of not leaving any tracking information that the seller can then sell or a hacker can use to rip you off.