Unknown Property Error - Custom Object

confused newbie here. I've read some previsous posts and I thought I had things right... apparently not.

I have tired value="{!origZip}" and get save error -

Error: Unknown property 'origZip'

If I try value="{!rater.origZip}" and value="{!Rater__c.origZip}"/ I get

Error: Invalid field origZip for SObject Rater__c

Yes, I'm guessing at this point.

Any help would be greatly appreciated.

public class Rater{

    public String origZip {get; set;}
    public String destZip {get; set;}
    public final Rater__c rater;

}

VFP

<apex:page StandardController="Rater__c">
    <apex:variable value="{!Rater__c}" var="rater" />
    <apex:pageBlock title="Spot Quote">
        <apex:pageblockSection>
            <apex:form>
                <APEX:OUTPUTTEXT value="Orig Zip: "></APEX:OUTPUTTEXT>
                <apex:inputText style="width: 50px" value="{!origZip}"/>
                <apex:outputText value=" "></apex:outputText>
                <APEX:OUTPUTTEXT value="Dest Zip: "></APEX:OUTPUTTEXT>
                <apex:inputText style="width: 50px" />
                <apex:commandButton value="Rate"/>
            </apex:form>
        </apex:pageblockSection>
    </apex:pageBlock>
</apex:page>