Why charge extra for multiple domains on shared?
 

I see that the host I was going to sign up with charges an extra $12 for each extra domain that you want to host. Yet other hosts allow unlimited domains.

Why would a host not allow unlimited domains? Different setup of their servers?

It is unnecessary. May hosts do have unlimited domains withing the same plan with no extra charge. Look up just199.com for example./

you must check offers section you will get many offers