"As to what it costs, you'd need to join Bluecoat and search some recent threads on igniters, costs, and life."
Haven't got a value for a 737 plug handy, but I've just checked our computer records and a B747-400 (Rolls Royce) ignitor plug is Australian $415.27 (circa U$ 245)... P/N YA211-25. Not quite as expensive as I first thought.
According to my sources, high energy General Electric ignitors may only last 200~300hrs.
Regards.
Q.