I'd look near the time ,you'll get some better deals ,
but JMC/SUNSET are quite reasonable

Dont know how cheap you mean but I found a week for all of you in Puerto Rico for £1846 from manchester 22/10/05

LAS FRESAS APARTMENTS
Self Catering
1 x 2BED APT sleeps max 6 adults
Panorama Holidays
Found on mytravel site , thats with a free child place.
They did have a few different accomodations as that one has mixed reviews as it is close to nightlife and can be noisy at times

I have just booked for the School week - In Scotland the holiday is week beginning 17th October. 2 families going 4 adults two children. Booked flights through A1Travel.com and accomodation through http://www.spanishluxuryhotels.co.uk we got two one bedroom apartments. A lot cheaper than booking through the travel agent. Price for family of 3 was £830.00. With regards to transfer from the airport. We are going to book an 8 seater mini bus on line which works out about 60 Euros each way split betwen the two families. Can't remember the link for this but there are various ones available example http://www.holidaytaxis.com

Good Luck