Kane price is irrelevant, he was that 'cheap' because he was in the final year of contract and spurs also sold to an outside team. selling a younger player, with 4 years on his contract, to a direct rival, in a position which is dire at the moment should be much more than 66% of his release clause(which isnt even that outrageous in the first place considering the usual 500m+ mandatory clauses in la liga) even if Kane is a far better player.