You can also try
MSC. Look under "Raw Materials". They may not have the selection a regular metal dealer would have but they do have some stuff and they are great to deal with and have prompt shipping.
I have never purchased metal stock through them but I have purchased a lot of other stuff between the account I use to order stuff for work plus my own personal account I have with them for my own needs.
Incidently, the KOP this year includes a CD from them.
