VoIP phones

How many lines can you have using VoIP phones over the analog system?

Unclear what you mean. The Cisco SPA 504G IP phone supports up to four lines and up to eight simultaneous calls.

How many Phones in total. I know there was a limitation with the Ooma office base station ans extender. Could I have 25 or 50 VOIP phones and extensions? your site is not very clear.

http://support.ooma.com/office/adding-a-new-user
Ooma Office supports up to 20 users. Create a user for each person in your company that will have an extension on your Ooma Office system.

http://support.ooma.com/office/ip-phone-overview-faq
Your Ooma Office setup can accommodate up to one IP phone per user. An individual user cannot have more than one IP phone.