Emma, that's the thought I had too, but realized it's probably not really safe, as those regular clamp lamp domes are not made for heat bulbs. The ones you can buy at the pet store (yes, they are a bit more expensiveYou can buy a lamp body there too (some are just the hood that goes around the light, others have clamp bottoms that will hold them on your tank) if you don't have another body you'd like to use at home (if you have a clamp light base at home, there's no point in buying another one!).
) have a ceramic base where you screw the bulb in that can handle the heat, unlike the regular ones you can pick up at the store. I do risk a little when I use a regular clamp lamp for one of my heat bulbs on my iso, but those are only temporary (I tell myself) so I don't use them all the time. Guess that doesn't matter if I'm using them for several weeks straight.