Redicously use of coils

My husband and I bought 2 Twisps from the Carnival branch about a year ago. At first it was the best thing that was ever invented. Now a couple of months later(of smoking Twisp only) we are both spending more money on coils alone than what we would have spend on cigarrettes. My husband's throat is a mess because of pure nicotene that he is inhaling and replacing coils is not solving the problem. I/we really felt this was the solution to our smoking habit but now it seems it was yet again a waste of money!