Insulation help

My upper floor in the house is unlivable. I put a thermometer to see what the temperature is and it’s reading 105F. Even with the AC blasting it barely reaching high 70s.

In the winter time the temperature drops in the 50s when there is no heat on. I plan to have the kids room upstairs but these conditions are not it.

Doing some research I see that spray foam is the best insulation. Anyone got their house insulated and have recommendations on who to use and roughly how much did it cost? Thank you!