How to build a linux based cheap (handheld ) computer

[Deboo ^]

Can someone provide some links to build cheap / inexpensive computer
(even with limited memory and no storage) which can run linux off a
usb stick and can be used for basic operations.

It will be helpful for poor people use a computer when handheld like
devices running Windows CE are still not as cheap as should be.

A DIY (do-it-yourself) kind of links also will do.

Thanks and Regards,
Deboo