Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Ipoh to Beijing as you normally would.
For a flight from Ipoh to Beijing, you will be flying from Ipoh. Ipoh (IPH) is just 2.1 km from the centre of the city. Ipoh is the only Ipoh airport and it handles 0 outbound flights to Beijing per day. 0 airlines have flights to Beijing from Ipoh on a regular basis.