Hi,
Window grills by labor will always work cheaper unless you don't waste material. Go with fabricator who is close to your place as they don't make window grill at site. You need to cross check with weight of the grills once they are done other wise there are lot chances of you loosing 100-200 ...

Guys pls help me out with carpenter rates for preparing aluminium doors & windows

And also welding guys rates for grille work for windows security grill etc
my watapp number 9980827230 and recommend good contractor