You never know when to book for sure, there is always a risk associated with it...
This year as per usual we left it rather late only booked a couple of weeks ago...But I say a deal come in from Easyjet which meant flight for our family of 4 were £950'ish inclusive to Mallorca. Then I used owners direct/holidaylettings to see what was available and found a villa with private swimming pool and private tennis court available for two weeks in August which came to only £875/week...Hire car, Skoda Yeti size was only £350 for two weeks...
Must admit that I didn't find Greece particularly expensive to dine out last Summer...I have not idea about Mallorca, but even if it is, there is always a BBQ at most villa so happy days