what is the difference between latex and foil balloons

One of the most significant differences between foil and latex balloons is their lasting ability. Foil balloons can stay inflated for a week or more filled with helium (great for longer events), while standard latex balloons typically last for a day filled with helium as they are porous and go cloudy. 

Latex balloons are more affordable especially if you are doing a large balloon garland installation. You can use a hi shine spray on the latex balloons to keep them looking shiny and fresh for longer.