If you are looking to have a fair amount of personal choice in what guts you are putting inside your rig for a reasonable price custom built PC, I would suggest
checking out Cyberpower's website. I bought my first PC from them nearly a decade ago to keep up with the steady graphical improvements in EQ and it is still reliable today. I've only been paying attention to affordable laptops recently so I'm not sure about similar companies/choices out there, but this is a decent place to start considering both customization and bang-for-the-buck.