Start with the purpose of the build and make the budget around that.
For instance a NAS build was obviously focus on the storage quality and PSU stability while a build for Rendering will have workstation components.
Use a PCI-E expansion card like this v
https://www.newegg.com/Product/Product.aspx?Item=N82E16815166038&Description=usb 3.0&cm_re=usb_3.0-_-15-166-038-_-Product