It depends on your character level how much it costs to unlearn a skill, increasing as the square of the level;
Cost = (200 / 3) * L^2 [color:"#3A495A"].......[/color](rounded down, if necessary)
At level 2 the cost is 266 gold, at level 50 it would be 167K gold; this is a steep, but reasonable price. I wouldn't want to change a mage into an archer this way, but for a couple of skills it is certainly doable, assuming the availability of gold and loot was not drastically cut back from Divinity (even then, there are battlefields you can use to get loot).
This is based on just 3 levels (only got to level 4 in the demo), so there could be a cap at some point, or it could go up faster at higher levels.
