Bread, milk and … prepaid plastic?

Plenty of supermarkets and drugstores are selling prepaid debit cards these days. The cards pitch plastic that supposedly isn’t fat with extra fees. No penalty fees. No minimum balance. No credit check.

“Pay as you go!” says the packaging for a card from Green Dot, the largest provider of reloadable debit cards. “You can’t get into trouble spending too much!”

Of course, you can get into trouble if you don’t dig deep into the list of other fees, which can top $70 a year.

First off, you typically will pay a fee just to buy the card. The Green Dot Prepaid Student Card costs $4.95 at the checkout. The Kroger Reloadable Visa Prepaid Debit Card is priced at $3. The Walmart MoneyCard has a $3 purchase fee.

And there can be other fees.

The Walmart MoneyCard, for example, also often charges $3 to reload money onto the card and may charge a $3 monthly fee unless some conditions are met.

And of course, to have any money to spend, you’re going to need to load the card with cash when you buy it.

The Walmart MoneyCard will enable consumers to have paychecks directly deposited on the card without a fee — and without a credit check or bank account. Or if you load at least $1,000 a month, there is no monthly fee.

Some providers, including Walmart, also waive fees for buying cards upfront if you go to their online sites instead of a store.

What’s more concerning about the packaging on the shelf — or even online — is that you’re not easily going to see a long list of other potential fees. You’re going to need to read the fine print inside the package or go online and review those fees.

So how can you end up with a $70 annual fee? Well, take that Green Dot card.

You could pay $5.95 a month to have that prepaid Visa — or waive that fee if, in a month, you make at least 30 purchases with the card or load at least $1,000 onto the card. Sounds good — unless you think that you make only 25 or 28 purchases. You have to keep track, and then do you make a few additional buys just to avoid the fee?

With that Kroger card, if you sign up for direct deposit of your paycheck, you’re not going to pay a fee to put that money on the prepaid card. But otherwise, you pay $3 each time you reload. You’d also pay a $3 monthly maintenance fee and $2 each time to withdraw money from an ATM. It also costs $1 each time you use the Kroger prepaid card to pay a bill online.

You should know

• Read the labels of prepaid cards. You need to spot the fees and rules.

• Go online for specific products and click on terms and conditions to see the list of fees. You also can compare prepaid cards at www.credit.com, www .lowcards.com or www.credit cards.com.

• Know your balance before you pay bills — you might not have enough on the card and have to pay the remainder another way. It could be tough to split payment methods with some bills.

• Pay attention to when the money that you’ve loaded onto the card will actually show up on the account; there could be some delays.

• Some cards tell you that if you try to pay a bill of greater value than your card balance, your bill will be declined.