Update 10.5.8 but disc drive is dead

I need to update to Snow Leopard, but it seems it is only available by disc and not download. My internal disc drive no longer works. Could I use an external disc drive to install Snow Leopard? If that is my only option, any recommendations for what external drive I should purchase? And am I correct that there is no way to download Snow Leopard? (I do have enough memory and drive space.) Thank you.