Window tinting is not rocket science, its more a question of prep and attention to detail.
Buy the film you want, and do it yourself. All you need is
1. spray bottle
2. clean water
3. meths to clean window glass
4. pair of scissors
5. scalpel (craft type)
6. small credit card type squeegee
7. some paper to make templates
a. cut paper to sixe of glass you want to cover, allow extra length to go under rubbers on wind down windows, and allow for top of glass to go into window channel without film on
b make sure glass is squeaky clean
c add a couple of drops of washing up liquid to spray bottle of clean water
d. cut film to size of templates (make sure you have film correct way round (handed)
e spray glass
f peel film and spray
g slide film onto glass
h and start from centre and squeeze out all water
i leave to dry , do not operate windows untill cloudiness is gone
j job done have a cuppa and think about money saved.
Dont tint driver and pass front windows, or windscreen(although you can do sunstrip at top if out of eye level (behind visor area)
You can tint over Heated windows but take extra care when cleaning HTSH