In order to be able to sell anything on BHW, you must be a Jr VIP or Marketplace Seller. To be eligible for Jr VIP membership you must be a member for 60 days and build up 100 posts. You will then be able to make the annual payment of $97 and upgrade your account.
If you don't want to wait, you can upgrade your to Marketplace Seller membership straight away, for $499.
Then you must create a sales thread in the appropriate Marketplace section. Please note that your thread will be reviewed by a Marketplace Moderator before it is approved and made live. Marketplace Threads cost $30 each.