What is the price fluctuating mechanism?

Digital currency prices of each token selling or purchasing advertisement is depending on the currently market price ( Taking Reference to the market price of Coinmarketcap、Binance、Huobi Platforms), and premium ratio that users setting on the advertisement , the calculation formula is as following:
Digital currency price of Selling ( or Buying ) = Current Market Price * Premium Ratio Setting On A Single Advertisement.
Each releasing advertisement from users can be setting a different premium ratio, after the advertisement is releasing, digital currency prices will fluctuating with the real-time market price and premium ratio.
Users can setting a positive premium ratio,so that they can obtain the digital currency prices that higher than the market price.
For Example, The current BTC price is 30,000 RMB, and premium ratio is 5 %, the buying/selling price of BTC shall be:
30000 * ( 1 + 5%) = 31500 RMB
If the current ETH price is 2000 RMB, and premium ratio is 5 %, the buying/selling price of ETH shall be:
2000 * ( 1 + 5%) = 2100 RMB
Surely users can also setting a negative premium ratio to obtain a digital currency pirce that lower than the market price :
For Example, The current BTC price is 30,000 RMB, and premium ratio is -5 %, the buying/selling price of BTC shall be:
30000 * ( 1 - 5%) = 28500 RMB
If the current ETH price is 2000 RMB, and premium ratio is -5 %, the buying/selling price of ETH shall be:
2000 * ( 1 - 5%) = 1900 RMB