I normally fly at Biggin, public transport into town in a bus away to the train station. Landing fees for aeroplanes not based is still a few £ cheaper than Shoreham (really disliked Shoreham, ATC was rude, landing fees crazy expensive... Best of all nowhere to go once you're there... Brighton was an expensive taxi ride away!). I think it's around £30 at Biggin at the moment, so that shan't break the bank!
But - have you considered Southend Airport? That has a train station right outside, 50mins into Liverpool Street, landing fee was £36 last time I went, and everybody there was really professional and really helpful. Big long hard runway, well lit at night... Has all the gizmos you may want in nasty weather too!! :-)
I wouldn't recommend a grass field at this time of the year. I heard Denham was nice but I've never been... Yet!
Otherwise it really depends on where you're going!