In my experience the most typical sort of lease (in Australia) is the "full lease". Here generally you lease a horse for a period of six months or more. The leasee is responsible for all fees - board, food, farrier, vet etc. The lesee can do virtually anything with the horse, although most contracts have things you cannot do, like you might have to alert the owner when you change boarding stables, or when you are leaving a state for a competition.
The owner does not have anything to do with the horse, nor the costs associated with it. Its the same responsibility as owning a horse without "owning" it. Also if anything were to happen to the horse you would be liable for those fees ie. If he damaged his leg you may have to pay the cost of the horse, or all fees if he is to be rehabilitated.
To me there isn't a "good" price for leasing. You pay what you have to pay - board, feed etc. I wouldn't reccommend having a horse that has to be kept with the owner. I understand why people do it, and personally I would never lease a horse to someone, but if you are somewhere that the owner is constantly watching you it can make you feel uncomfortable and then its not really "your horse". If you are going to be paying all those fees you want it to be as if it were yours.