Just like Bitcoin, the price of Bitcoin Cash (BCH) is determined by market demand and set by those who buy and sell it. Coins.ph does not control the price of Bitcoin Cash (BCH).
To see the current buy/sell rate for Bitcoin Cash (BCH), just go to your main wallet screen, and tap the Convert icon. Converting from PHP to BCH would reflect the current buy rate, while converting BCH to PHP would reflect the current sell rate.