Things only get cheaper nearer to their dates if there is little demand for them. (That applies to flights, holidays, concert tickets and lots of other date-specific offers as well).
There will be plenty of people seeking cheap holidays to the Canaries at this time of the year (because its the only short-haul destination which is still likely to be quite warm), so I'd be surprised if prices dropped between now and next Saturday. (Indeed, many flights might become full altogether, so you'd be unable to get on them at any price).
I'd book now!