Not much, depending how you want to go about it, buying 100-200 seperate hosting plans or buying one hosting plan with unlimited sub domains and putting them all on that
Minimal traffic is not an issue. You can pretty much buy a basic hosting package that allows unlimited domains and you will be fine. I wouldn't think anymore than $10-$15 a month.
I've used netfirms to host tons of sites like that and works pretty well for me. http://www.netfirms.com/netfirms/web-hosting/plus.bml
it costs you around $6 per month Please follow the link http://www.hostdepartment.com/nolimit-features/
Not all providers allow for unlimited domains on shared hosting. You may want to make some detailed inquiries before you solidify your decision.
I would strongly recommend against run a server from your house. Most ISP's will terminate your service if they find out you are doing this. I would vote against a shared hosting environment for this amount of domains. I would look for a VPS.