One of the best things you can do to be eco friendly and cheap is fix old stuff rather than buying new stuff. A great example is electric shavers and beard trimmers – the batteries stop holding a charge after a few years and you can easily spend $50-200 on a replacement – or $4 putting in a new battery.
Most modern electronics with batteries are intended to be opened with a screw to remove the batteries for recycling. However with a bit of soldering you can put in new batteries. I did this a few years back with my old shaver and its still working like a champ – going to be redoing my beard trimmer next.
Haven’t soldered before? These are really simple solders (here’s a tutorial) and its a great skill to repair simple electronics. A soldering kit can be had for about $15 and will provide years of repairs.
I get my battery kits at HQRP but there’s a variety of sources.