I always find it strange that someone spends hundreds and hundreds of pounds watching GFC play home and away, (tickets, travel etc) then will not spend a couple of quid on a coke or a pork pie to enhance their visit to the ground, lol, what the hell does it matter, but that's just me.
There is not much you can do about ticket or travel prices - except if ticket prices go up on the day and then you buy in advance.
But there are ways of making your match day experience cheaper, bring your own food or drink or look for somewhere to eat and drink around the ground, in-terms of value for money you get more for your money buying your food and drink from a cafe or fast food outlet, then you would if you brought the same food for the same price inside a football stadium.
Even at Priestfield Stadium I go to The Co-Op to buy drinks as you can get two for £2, rather then paying the expensive prices inside the ground.