New... anywhere between £100 to £250
Also depends if yours is a 1.8 16v or a 1.6 16v and if its mk1 or mk2.
Only one listed for a mk2 1.8 16v.. about 20 listed for a 1.6 16v mk2.
Best to ask a trusted motor factors, a garage doing the work, or at Fiat parts dept.