Portal access for outside people

Hi gurus,

I would like to how can outside vendors can access our SAP EP to access certain info from ECC thru ABAP Web Dynrpo application. We have around 200 vendors, do we need to purchase 200 SAP Licenses for them?  I heard that sap license is not required for portal users, only one extra SAP license is required between ECC and EP. How far is that true? If this is true, how to hanle that in ABAP WD app?

Thanks very much.