hi, i want to ask the bus price or any suitable vehicle from Peking University to Great Wall.

Do you refer to Badaling Great Wall?
Take metro line 4 from East Gate of Peking University to Xizhimen Station, Exit A2. The metro ride takes about 15 minutes, and costs CNY 4. Then, take S2 train to Badaling from the nearby North Railway Station. The train takes about 1 hour, and the fare is CNY 6.:)

Hi,dear! You are going to Badaling Great Wall, right. Take metro 4 from East Gate of Peking University to Xizhimen Station, and change to metro line 2 to Jishuitan Stattion, Exit B2. The metro ride takes about 22 minutes, and the fare totals CNY 4. Afterwards, walk to Deshengmen and take bus line 877 to Badaling for CNY 12 (about 1 hour).