What scammers do is they get you interested in the job so much that you will agree to send them money via Western Union to pay for your (fake) visa and (fake) safety deposit/other expenses required by "immigration" (Warning: never send money!). It's usually around US$700-800. If it works the first time, they will ask you to send money again, for something else. When you stop paying, they will stop responding to your emails.