Sounds expensive to me. We only paid 280 for a 5 night girl scout camp that includes all of the activities you just named along with swim lessons and a few other activities. We did have to pay $30 extra for the caving field trip, but that was optional.
The camp should have given you a supply list.
Here is the list for my daughter's girl scout camp:
Clothing
T-shirts, one per day + two extra
Shorts, one per day + two extra
Socks, one per day + two extra
Shoes, tennis shoes or sandals
with backs -- two pair
Shower shoes (flip flops)
Raincoat or poncho
Pajamas or night shirt - three sets
Two bathing suits
One pair long pants
Underwear, one per day + four extra
Gear
Two wash cloths
Two bath towels
Two beach towels
Twin sheets
Blanket or sleeping bag
Pillow with extra case
Laundry bag for dirty clothes
Backpack or fanny back
Flashlight with extra batteries and bulbs
Non breakable plate, cup and eating utensils
Water bottle
Plastic bag for wet items
Toiletries
Sunscreen -- SPF 15 or higher
Bug spray -- non aerosol
Shampoo/conditioner
Brush/comb
Soap
Deodorant -- non aerosol
Tooth brush/paste
Bucket to take to the shower
Sanitary items
Optional items
Camera
Stuffed animal
Book
Stationery, pen and stamps
Coloring books and crayons
Extra glasses and contacts
Sunglasses
Stadium cushion or camp chair