costing a lot of money, as in: A large front lawn can be expensive when you add up the water bills, fertilizer bills, and energy consumed in mowing it regularly
If something is expensive, it costs a lot of money. Wine's so expensive in this country I get very nervous because I'm using a lot of expensive equipment. = costly inexpensive + expensively ex·pen·sive·ly She was expensively dressed, with fine furs and jewels cheaply. costing a lot of money cheap