Trustworthy shops?

Hello! Im interested to buy a secondhand macbook m1 16gb ram for my sideline work.

Not really an apple expert, just started using m4 in my main work last year and sooobrang sarap nya gamitin so I want to invest for my sideline (thinking VS Lenovo thinkpad)

May marerecommend ba kau na trustworthy shops/pages where I can buy one? Is going to greenhills a good idea?