Ongoing costs can be surprising. Initial kit can range from £100ish to thousands, depending on what you want to play. Then comes the ongoing event costs, and more kit, and wanting an in-character tent, and 'looks the part' cooking equipment, and so on and so forth.
This event, I've already paid for. So petrol there and back, probs about £30, sleep in car, £40 for cooked meals all weekend, lord knows how much for booze (Mead is about £12 a bottle, and pints around £3..). In theory, that's my spend, as I'm fully equipped otherwise. But I could do with new trousers.....split my current pair about three years ago, and maybe a new undershirt....
But hey, what does the price matter when you're enjoying yourself!