When looking at an online mentoring system, I would caution prospective buyers to pay attention to consulting costs as part of the package. If the software for a mentoring program is comprehensive, then there should be little need for a lot of consulting time on the part of the vendor. The system you are looking at should have all the components already created and should allow you to edit the content to suit your needs.
As a result, you should not need to pay for additional consulting fees when you license the product to create and manage your program. What your contract should include is all the capabilities of the software, tech support and some small additional time for consulting if needed.
If additional consulting is twice the cost of the software, consider finding another vendor.