What is the bestes and cheapest way from Chengdu to Leshan ?

Both Xinnanmen Bus Station, there are buses to Leshan. The bus fare is CNY45, and the bus duration is about 2 hours.
Your bus will arrive at Xiaoba Bus Station; from there, you can take bus 13 to the scenic site.

There are also bullet trains from Chnegdu. Duration is about 1-1.5 hours. Ticket fare for first class is CNY65 and second class 54. Upon arrival, you can take the sightseeing bus to the Buddha site.

If you want to take the boat to sightsee the Buddha, you need to go to Baxiandong port.