120V heater pad
This page explored 120V ac heaters. Natural choices are heater pads, but these are expensive and custom items. So we made our own nichrome heaters, which have the advantage of complete flexibility for power and size. They are time-consuming to wind without a Winding Jig.
The nichrome DIY heater element works, but the connection from nichrome to wire is difficult as it goes from copper to steel and there is galvanic corrosion. Further, we run the heater at high temp for fast heat - so we have had the nichrome elements burn out regularly. Solutions are to run the nichrome at about 600 C max, well under its 1000C rating. Another great solution - which turns out to heat faster because it doesn't require insolation over the heater element - is a halogen light bulb.
Halogen bulbs get hot - several hundred C - and radiate about 90% of their energy as heat. Thus, they are fast, effective heaters, and becuase no insulation is used over them, they can heat the 3D printer heat bed rapidly.
- Use resistors instead - 
Halogen As Heater
Moved to Halogen Heat Bed