the cheapest...
look here
every guitar has different characteristics...
none of which matter until you learn to play one.
so if you pay more than 100 for a guitar, you may make a big mistake that you won't know about for quite a few years... and a 100 dollar guitar will sound just fine.
so, go cheap - learn to play - then experience different sounds before you decide to put out big bucks for the one you "think" you really want.
the down side to electric is that you can't hear them unless plugged in - so there will be additional cost to start up...
unless...
you have access to a old sony walkman - or any other portable tape player (which can be rigged to play an electric guitar just fine)...
i have a left handed fender electric/acoustic - i really love the richness of an acoustic sound - and occasionally like to be able to plug in and blow my brains out...
there is also the possibility that you may lose interest or simply just not have enough time to learn - and nothing is worse than a 500 dollar guitar sitting in the corner laughing at you...