re5. Depends on application. For the applications you have listed (running a prep gel or a quick check to see if DNA was digested) I also do not use $1000 power supply. But, as you said, for "special" applications I would use it. For $1000 one can get a high voltage PS, something you need to run long gel, or pulsed field gel. Lately, I have actually switched from running gels to using a chip-based system (Experion) from BioRad to analyse proteins, DNA and RNA. The system is based on capillary electrophoresis, but provides a lot more data at a shorter time.
Of course, I would not setup asummer program for students using $1000 power supplies. DIY setup with a transformer to give ~ 50V and a simple bridge rectifier is sufficient. I would also add a fuse and try to run these from a GFI outlet. High-school students are too curious sometimes for their own good ( I've been in high school too some 30 yr ago).
Re: Drinking straw electrophoresis!
Of course, I would not setup asummer program for students using $1000 power supplies. DIY setup with a transformer to give ~ 50V and a simple bridge rectifier is sufficient. I would also add a fuse and try to run these from a GFI outlet. High-school students are too curious sometimes for their own good ( I've been in high school too some 30 yr ago).