I was wondering whether it would be possible to buy a PA and some PA speakers instead of getting a half stack and cab. I know all the tone advantages of a half stack and cab however if i'm running my guitar through a preamp then it would pretty much solve tone issues (of course nothing probably compares but still). The reason i'm asking this is because I need a cheap solution to my problem. My problem being that i play guitar, and sing, and am poor :). Basically i would need an amplification system that would allow me to do both and keep up with my bands mighty 100watt stacks (only jamming now adays so they are hardly set loud but still).

Any suggestions on the matter? Once again I know there are obvious tone differences in the half stack that make them sound more hearty and so on but i'm really strapped for cash, and i can always get a half stack later on.