Is it true that the price for the movies at all cineplexes like siam paragon , EGV, Major charge less on wednesdays ?

On some days they do have special prices, also they have special prices for students too, just check out their websites

yes, as far as i know, every movie theater has discount rates on wednesday. i dont have the exact numbers in my head but i know it's quite a bit. even paragon has discount, but now as much, i believe there it's 100 as opposed to 60 at the others. but not 100% sure.