Basically rather than making it all from scratch I will call it piecing together because what I usually do is thrift shop for pieces and parts and modify them into a cosplay. I then make my own props. So I guess it is a bit of both buying and making mixed with alot of creativity.
I am going as young Rosette Christopher (pink dress, boots and braids) and my bf is going as Chrono in his boy form(original outfit he was wearing when she first met him) both from Chrono Crusade ^.^