Cheap Tool For cutting a small circle

[jolly_dodger]

Need a cheap 1 use tool for cutting a 50mm circular aperture into aluminium, i need (want) to cut a hole into the hard drive cage in my and 5Nhalf inch bay for routing cables in my Thermaltake Mozart TX, Any old cheap 1 use tool will do finishing does not have to be perfect as itll be out of site and i will smooth the edges off myself if needed.

Anyone any ideas?

 

[jolly_dodger]

Aww shucks, thanks guys, My step dad is a joiner so he has loads of drill hangin around, just that all his tools cut wood... so i think i can manage finding a bit.

Once again, Thank you guys

 

[jolly_dodger]

Don't even consider using a electric drill with a hole saw bit, use a bench drill, with your work clamped down.

Dont have a bench drill but i can clamp it to a bench, like i said it doesnt have to be neat, but my step dad is a beast ill ask him later but im sure he can make it neat.