Thanks guys, very interesting answers, clear as water that buying a laser under 20$ is a lottery. The thing is that I will use it ocasionally, so my aproach will be trying with a cheapo one you have recomended, and if it not work, then I will go for a better one.
I have three 5mW green lasers pointers, 2 from ebay and 1 fron DX. None of them works as I would like. May be I can see the beam just the 2-3 secons after I push the button, then it becomes really weak or erratic. This behavior worsens a lot when temperatura is cold. All of them are the typical...