I want to make a bunch of meringue cookies, but I don't want to waste a bunch of eggs. If I buy something like Egg Beaters Whites, would that work?
Egg-whites in a carton are usually pasteurized. Pasteurized eggs are not great for meringue because the heat from the pasteurization process negatively affects the proteins in the whites that make for good meringue. With a lot of whipping (and more cream of tartar or other stabilizers) pasteurized egg whites (whether from pasteurized eggs or from cartons) can make meringue though it most likely won't be as stiff as those from non-pasteurized eggs.
I would suggest getting regular eggs and trying to use the left-over yolks for something like creme brulee.
I looked it up in a couple of pages and the difference between egg whites and egg beaters is the texture with the later being a bit watery and may require more whipping time for it to achieve a solid form. So probably you might want to give it a go try and make a meringue cookie but it may come out as good as the one using natural egg whites. The difference between the two is given here
Year ago, you used to be able to buy instant meringue mix. The packet had egg white powder and sugar, and some food acid. Just add water and put in the mixer machine. They worked great, and often gave better results than fresh eggs
Haven't seen them in the shops for years, it's all sugar free, and fat free rubbish
Even though it's more of a hassle, DEFINITELY use fresh eggs. I've been making meringues for years with no problem (unless it's humid and in that case I wait for another day).
I bought a couple of containers of the pasteurized egg whites (they are more runny). Made 4 batches, whipped the heck out of them, oven 365 for 30 min and left them in the turned off oven an extra hour or more. They were just ok, not as fluffy and certainly didn't make as many because the volume was low.
Going back to the fresh eggs. Incidentally, I freeze egg whites (don't overfill container though) They thaw well and they can be used to make great meringues.