We have customer who is looking for us to develop an app for him on force.com. My customer will want to have tiered pricing for this app which makes available certain features and functions based on which version you subscribe to for his customers. I'm confused about how salesforce will charge us? On Salesforce's website it seems pricing for force.com starts at USD 25 per/usr/month and go all the way to 4,000. My customer will want to have 3 versions of the app with pricing ranging from USD 5 - 20. How will this work?

I see a lot of resoitces online to convert an unmanaged package to a managed one. Do we have the ability to convert a managed package to an unmanaged one?

We have a client who supplies construction material to architects, interior designer. They need a way to track projects that their customers(architects, interior designers) are running and then how much much they have made on each of their client projects. 

Each month they collate information from 3rd party sources about construction projects approved by the givernment in their area and input all those projects as leads. The problem is some of the contacts may aleady exist in the system and therefore there should be a way to indicate that the contact already exists. Would you suggest we don't create a lead in this case and just use accounts and contacts?

Looking for suggestions and inputs on how to design the applictaion.