I would like to resister a dot US but where is the-
cheapest place.

I'm not sure about being the cheapest, but these are cheap for .us domains:

godaddy.com
domainsite.com

Remember that you cannot privacy protect a .us domain. If you don't intend to do that, no problem. It could be upsetting if you were expecting privacy protection because the registrar may sell you a unit of privacy protection in the same order without any advance notice that you can't apply that unit to that domain. Even though you could probably get a refund on the unused privacy protection, you couldn't unregister the domain that will display your information in the whois.