If you aren't worried about safety then you can use e.g. a full bridge rectifier hooked up to 110 V AC to get a usable (but shitty) agarose gel power supply. I

If you aren't worried about safety then you can use e.g. a full bridge rectifier hooked up to 110 V AC to get a usable (but shitty) agarose gel power supply. I really don't recommend this but it does show how easy it can be.