Try the following links for flights :-
British Airways they have a budget airline GB airways that fly out of Gatwick
http://www.monarch-airlines.com/
http://www.easyjet.com/en/book/index.asp
http://www.thomsonflights.com/bd/home?formAction=initiateFareSearch
http://www.bmibaby.com/bmibaby/en/index.aspx
http://www.flybmi.com - they fly out of Heathrow, but are very specific on over weight baggage I think they look to get back some of the discount by charging you for overweight baggage.
http://www.tarletontravel.com these specialise in flights to Almeria, although we haven't tried them yet. They will also arrange airport transfers if you don't hire a car.
http://www.rainbow-flights.co.uk/
http://www.almeria-network.com/menu/flight.html
http://www.freedomflights.co.uk/
For airport parking and hotels :-
http://www.holidayextras.co.uk
For travel insurance, we saved a lot of money by taking out a 12 month policy which came to £50 for a family of 5, if you plan to travel more than once a year then this is very cost-effective. Our policy came from http://www.direct-travel.co.uk
Taxis can be found at all the airports. From Almeria, the fare is about 80 euros, however if you book your flight with Tarleton Travel they offer airport transfer for 45 euros. However you may have difficulty getting a taxi back from Mojácar unless pre-booked.
You can also use Shuttle Direct their fare from Almeria to Mojácar averages £12 per person.
For information on local airports, please click on the following links, courtesy of the excellent Viva-Almeria website
http://www.viva-almeria.com/Almeria_Airport_LEI_P424.php
http://www.viva-almeria.com/Alicante_Airport_P425.php
http://www.viva-almeria.com/San_Javier_Murcia_Airport_P426.php