Reverse flight, traditionally in the UK, it was a case of instruct, turboprop then move to jet; these days there is an increasing trend of pay to fly schemes on the 737 and A320s, which means there are less opportunities to move from a turboprop to a jet with a company funding the rating.
Even though Jet 2 took on some turboprop pilots they still had to fork out 20k for the type rating.
Just to add to my post the ATR rating cost just under 18000 Euros.
The 737 rating +300 line hours works out at about £33000, but adding in four to six months of living expenses a good 8 to 12K, so total, so looking at over 40-45k pounds of expenditure.