How to Encrypted Password before sends the server.

Hi:

I have a question, I don�´t know, if this can do, I think that is possible,

I have a site into INTRANET, then the user sign in, and your password travels to the server. I am searching how to send the password encrypted, and the server unencrypted the password,

I am hearing about https, I know that I need pay for this service, but maybe  exists other way for send  "information secure" , I am thinking , build a program that encrypted the password, and

the user send this information, but the user  donÃ?´t wants do this work, What can I do?, I think in the user, and the security....

Thanks for your help..       
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