Another advantage of ARC is that you can check the framework for bad glue joints & make mods without having to uncover and then recover or patch. But the price of covering material must be factored in and you can usually buy an ARF almost as cheap as the ARC. An example of this is/was the TT Fun Extra. The ARC & ARF versions are around the same price. The ARF is a piece of junk....the covering is shelf paper, the web in the wing has the wrong grain direction, and the tail structure needs reinforced. Many bought the ARC and corrected the shortcommings and put on good quality covering but when you factor in the extra expense you would be better off buying a properly constructed ARF funfly with real iron on covering......to say nothing about your time.
As for scratch building....its very therapeutic .....if you have the time. As far as balsa prices.....if you mail order you can get the balsa at a fraction of the cost of the precut kit. The disadvantage is that you cannot select unless you are near a wholesale supplier that also sells to the public. But if you buy from your LHS you are going to pay twice the price and it begins to approach the price of a precut kit. If you do lot of scratch building like I USED TO it pays to buy mail order in bulk and then you can grade out the balsa and that usually works out well.
PilotFrog