In email marketing there are 3 types of emailing, dedicated, shared and service.
Any shared host can email, although they impose limits , but they are the cheapest
for dedicated you can send all you want, however ISP such as google,hotmail and so on will
block you if you send to much.
If you want the best inbox rate you need to use a service , these are the most expensive and require less than a 8% bounce rate
http://www.icontact.com : service
http://site5.com: shared hosting
http://amazon.com/ec2: dedicated hosting