Check out the American Astronomical Society's website about the eclipse, including their approved list of eclipse glasses suppliers:
Beware of purchasing directly from Amazon, Temu or other online retailers; they may not be legitimate and could be dangerous.
In addition, NASA warns that viewing any part of the bright Sun through a camera lens, binoculars, or a telescope without a special-purpose solar filter covering the optics can cause severe eye injury. You also shouldn't look at the Sun through a camera lens, telescope, binoculars, or any other optical device while wearing eclipse glasses or using a handheld solar viewer. The concentrated rays will burn through the filter and damage your eyes, the space agency said.
To protect your device, Duncan recommends using a solar filter that can be attached to a phone camera or even using a pair of solar-viewing glasses in front of the phone camera. "The filter that protects the phone is exactly the same as the glasses that protect you," he told KXAN.
One of the best ways to view a solar eclipse is through a pinhole projector where you look at a projected image made through a pinhole in cardboard paper. Or even easier, grab a colander from the kitchen (not the mesh kind, the one with holes in plastic or metal)!
A. Get a cardboard box. Punch a hole into one of the ends (I use one of the smaller ends to make a longer path so a bigger image). Since the cardboard may have ragged edges from the punched hole, I generally just make the cardboard hole larger and then cover it up with a piece of thick paper and punch a smaller hole in it. Put a sheet of white paper into the opposite end. You may need to tilt the box, propping it up, to see the image.
B. For a brighter image, if you just make the pinhole larger, it will get fuzzy. Instead, make a larger hole but use a pair of inexpensive reading glasses to focus the image inside the box. The image still won’t be very large, but it will be brighter and in better focus. You may need to adjust the placement of the box (the best strength of the reader depends on the length of the box: 2 or 2.5 magnification works well with a 14-16 inch box).
C. This shows the image inside the box. For a neat solar projector using a drinking cup and readers, see Rice Space Institute's "plastic cup solar projector" activity
Source: American Academy of Opthalmology and American Astronomical Society, July 21, 2017, https://www.aao.org/eye-health/tips-prevention/safe-solar-eclipse-viewing-infographic.
The Sunspotter uses optical projection to produce a magnified image of the Sun that can be viewed by many people at once without risk of anyone looking into a bright beam of sunlight. However, it's over $500. A less expensive but similar alternative is the Solarscope, around $290.