If you get a set of auto tubes (like the Kenko ones) they are a very easy to use - you fit them between the camera and lens and forget them, the camera will work exactly the same as it did without them. The cheap ebay tubes are pain to use and a waste of effort.
As tubes have no glass in them you will not lose any IQ when using them, unlike the raynox which will affect IQ.
As I've only used tubes with prime lens's I'm not sure how well they will work with the lens in your kit bag, but with a nifty 50 you would get a bit more than 1:1, about the same as a true macro lens, and if you got a 100mm true macro lens you could still use the tubes giving you about 2:1.
If you do a forum search on raynox you will see some excellent results produced by the raynox but the lens you stick it onto will influence the IQ.