Hello,
As per your requirement I can understand you need to send 10k emails using outlook, but outlook is only an application which helps in sending and receiving emails, number of emails depends upon the mailing engine, if you don't have a mailing engine or if you have not subscribed for a mailing service then first step is opting for such service. Cheaper one will be having your own mailing engine.
After this step is done I can configure outlook to send mails using the mail engine.
Thanks