+1 for MXRoute if you're just looking for an affordable alternative to Google Apps and not some fancy API. They bill by storage and not by the number of account

+1 for MXRoute if you're just looking for an affordable alternative to Google Apps and not some fancy API. They bill by storage and not by the number of accounts, and they offer discounts around the year if you look around. Also don't be fooled by their frontend that looks like some run of the mill shared hosting. Their backend is absolutely professional.