I have written emails to the sales department at Wild West Domains and it takes around 2-3 days to get a response. They also want personal tax form information if you sell domains. Be sure to read the fine print.
I have found Tucows - www.tucows.com and Bulkregister - www.bulkregister.com to have a faster email responses to questions. I don't know about the domain prices though.
Enom - www.enom.com might also be another option for ya.
Most cost around $99 to open a reseller account.