Paper or plastic? How about pleated polypropylene made from recycled water bottles?

It’s gotten more difficult to check out from a grocery these green days. You need to remember to bring your own bags.

As they were during the last green revolution in the 1970s, reusable shopping bags are the rage. Whether they survive this time is anybody’s guess.

Meanwhile, everybody seems to be selling them. Stores would love to get rid of their free bags. They are added expense. If you can sell someone a reusable bag, all the better.

You have a vast universe of choices, ranging from 89 cents to more than $50 for a designer bag. The 89-cent one quite possibly is better constructed than the most expensive one.

So you think paper bags are more environmentally friendly? Paper takes 98 percent more energy than plastic to produce and generates 70 percent more air pollution. Paper requires 98 percent more water.

If you’re in the reusable bag market, you need to know a few things. The most durable ones are made of polypropylene and stamped in a woven pattern. These often sell for less than $1 each.

Good bags have a stiff plastic sheet acting as a bottom insert. It keeps the bag open for loading and unloading and folds flat for storage. The bags sport a rack loop to hang the bag while loading at the checkout.

Polypropylene is waterproof and almost impossible to tear. Look for bags that have handles stitched all the way down to the bottom. One bag can hold about four plastic bags filled with groceries.

A good shopping bag

- Is waterproof and tearproof

- Has handles sewn down the sides

- Has a bottom insert

- Has a rack loop

- Costs less than $2