Hello,
It seems as you go to all the site to look for tickets as the price change when you log from your PC or your Phone or another computer for the same flight on Kayak or other site you will find same time price of 200$ . It is very strange and if you go back after half an hour there is another story it is very complicated and tricky and not fair at all that the price jump by 200 or 300 on the same flight from the same site after a short period of time