It sounds like you don't wanna spend too much on acoustic treatment and stuff, which is alright especially cause you are just starting. your best bet for using a condenser mic without picking up too much background noise is to use a basement room if available, if not then pick a room with no windows. Don't let the mic get close to any electoronic devices that are turned on(computer monitor, fride/freezer, whatever). Also, don't record when something noisy is happening in your house. You will proabably not have any "background noise" issue when setting up like this.
Another method for starting out, for vocals anyways, would be to record in your bathroom. You get a cool reverb effect(sounds alright for a newb) and you will get minimal noise as long as you dont have noisy pipes.
Simon