Here's an extract of the Sitefinity 4.0 license agreement:
"The Software may be used only for your internal purposes that do not generate profit; you may not use the Software to create a website that generates or supports the generation of profits for a for-profit organization
I presume that in this case it's a website that does support the generation of profit, rather than just serve community purposes, so you should consider using Sitefinity 4.0 Small Business edition for this.
Grisha 'Greg' Karanikolov
Sitefinity Solutions Consultant