I don't think you can count sundries on a game day as that depends on how individuals play.
Travel expenses can't really be compared either.
But regarding entry fees...
At sites I know, Red Alert in Bucklebury is the best value at £27.50 (used to be £25) including lunch (just a pizza tho I think)
The other site I frequent is Skirmish Wycombe at £30 including lunch (good food) is fair too.
I try to bring sundries such as BB's, gas, snacks and water so I don't spend so much there but I'll usually buy a few extra drinks if needed.