Will the price of the iPhone 6s increase after the release of the iPhone 5se as the price of 6 increased after the launch of 6s?are there any chances or so?
Again, there is no iPhone 5se. Nor will there be one. If Apple announces a new 4" phone, it will be called the iPhone SE. So far it's only rumor. Why don't you hold off on all these questions until Apple makes an announcement?
No, the price points of any existing devices will not increase. Apple needs more phone sales, not less.
That being said, you're mostly likely looking at a $450 starting point for an unlocked 5se/SE. Again, everything is rumor, including what the device will actually be called, so we won't know for sure until the 21st. Luckily it's close!