I would think it depends on the job requirements. If they are just answering incoming phones, chats, and tickets 5 days per week I would say anywhere from $2-3k/month salary, no commission.
If they are doing sales outreach in addition, I would throw in a small commission for motivation. But honestly I just dont know if that's required for this type of business. I would rather invest in white hat seo, ppc, social, and use a crm for leads.