If you are considering the interesting and rewarding hobby of laser building there are safety issues that must be understood.
Even a cheap laser pointer of less than 5mw from the pound shop can cause temporary spot blindness should it bounce off of a reflective surface into some ones eye.
When you decide that what you want to build is a red laser capable of lighting matches, burning plastic etc you must buy yourself a pair of laser goggles, as a 200mw beam in the eye will almost certainly cause permanent damage to the retina.
Sun glasses will not be safe, you need a pair of safety goggles designed for the colour (wavelength) laser you will be using and if you are going to show the laser off to your friends, they too will need goggles. Do not think "I can do this safely, I don't need goggles" if you are burning you will need to stare at the focused dot for a number of seconds, this will cause damage to the eyes.
Red burning laser
If you progress to powerful green and blu-ray lasers you will need goggles designed specifically for those colours (wavelengths) as well.
You may decide that you need more power for faster burning, this could take you into the realms of infra-red lasers.
Near infra-red laser
Infra-red lasers are commonly invisible which makes them much more dangerous than blue, red and green. If you should get a flash in the eye from one of these visable wavelengths your sight may be saved by our natural "blink reflex". With infra-red you will not know it is shining into your eye until the damage is done.
Hemorrhage of retina due to laser strike................
This page is titled "lasers are not toys", they can be dangerous to yourself and others if they are misused. You only get one pair of eyes, look after them.
BUY SOME GOGGLES!
There is a lot of additional safety information to be found on laser pointer forums
there are often special offers on laser goggles in the group buys or in buy/sell/trade. information on companies that sell goggles may also be found here. If in doubt join the forum and ask questions, the members are knowledgeable and very friendly.