Please you decide what laser shall I get?

[Hydrogen]

I'm going to buy a laser, not a bad one from ebay, but one from odiforcelasers.

Focusing Red Laser Model SD302 80mW - Detailed item view - OdicForce Lasers Online Shop

or


Heavy Duty Side-switch Style Green Laser 15-20mW - Detailed item view - OdicForce Lasers Online Shop

or

PowerCheck Laser: Compact Green (532nm) Laser with Power Options up to 50mW - Class 3B Laser - Detailed item view - OdicForce Lasers Online Shop
Please decide what will last longest looked after.

 

[InfinitusEquitas]

Really depends what you're gonna use the laser for. Since you are sticking to lower powers I would definitely go with green so you have at least something of a beam.

Go with option 2, batteries are easy to get and cheap.