Well alot on here object to pay to fly to , you have to do what best suits your circumstances.
In 2007 I must have taken a 30000+ pay cut to become a full time instructor, not to mention the fact that it also cost be 5000+ of my own money to support my living expenses for the year I worked as an instructor. Although I did secure several interviews from working as an instructor, I made a very poor choice of my first multi crew job and ended up getting laid off after six months. So all in all ending up with a handful of hours of an old generation turboprop doesn't really get the CV noticed.
So to me the real cost of instructing full time for a year was 35000 pounds.
The fact remains I would have been far better off staying in my previous job (which I am now back in anyway) for a further tweleve months and raising the cash for a pay to fly scheme, irrespective of what is said on here 500 hours on a 737 may well have got me a job at Jet2 and right now would have made me eligible to apply for BA. I enjoyed instructing, I have some wonderful bar stories about flying an old turboprop, but the fact remains a pay to fly scheme would have much been much more useful for career enhancement.
The thing that has probably most contributed to the pay to fly schemes is the fact instructional pay is so low and most turboprop jobs are also quite poorly paid.