There are tons of hidden costs in operating an airfield -- I'm not at all surprised at the fees at your club

My club membership fees are $100.yr with MAAC membership extra ($75/yr). We fly off grass -- one 350' runway & one 200' cross-wind runway. We only pay $200 yr to lease the land (an incredible deal) but our fuel bill for grass cutting is ~ $500/yr & upkeep on the two lawn tractors is about the same. Then there is fencing, sun-shades, barbecues, lighting road grading, etc. etc. etc.