Cheapest route to chengdu airport and zhuge liang temple?

I assume you mean the Memorial Temple of Marquis Wu (Zhuge Liang)/ Wuhouci, they are only around 4.5km between. You can take local bus no. 1, 8, 334, or 335 (CNY2) to reach there. To get back to the airport from Chunxi Road, you can take subway line 2 to Tianfu Square and transfer to shuttle bus line 2 to reach directly.

If you refer to the Zhuge Liang Temple in Mianxian County, you can take airport shuttle bus line 2 to North Bus Station. Take a bus to Hanzhong first and transfer to another bus to Mianxian County. After that, take a taxi to the temple.