Do I need to have a new hosting plan everytime...

Hostgator has "unlimited" domains in their $15/mnth plan. The only problem you can run into is unlimited domains does not mean unlimited bandwidth. If your sites become a burden on their server, you will have to upgrade or shut the account, but I haven't had any problems except when a plugin or two was misbehaving and they contacted me and I disabled it. Some other hosts have unlimited plans also, but I'm a Hostgator fan.

Depends who you have the account through and the plan you have signed up for. They are all become much more competitively priced so if yours costs you $15 for every site, move or sign up to another service. FYI there are services via WF for a low price but I have had patchy up / down time with those so far.

Hostgator or Hostmonster are excellent choices. Set up each site as add-on domains in your cPanel and you will be all set.

Its is a good idea having a reseller account if you have many websites . Also if u decide to sell some of your sites with a reseller account you can offer your buyers hosting and make some cash from it too.

Most hosting accounts will allow you to host multiple domains. Any good plan allows for this. Reseller accounts help to keep things more organized if you plan to set up a lot of sites, but if it's just a few sites, using the addon domain feature will be enough.

As others have already mentioned, Hostgator for the win.

I would recommend you look into a reseller account, and I'll explain why.

When you have 1, regular shared hosting account, it runs as 1 user on a server, no matter how many sub domains or addon domains you have. If for some reason one of the, let's say 50 addon domains starts using tons of CPU, the account will be shut down to keep from affecting other accounts on the server. When that user gets shut down, so does every "addon" website.

There's also a major security risk with using addon domains. Should one of them get compromised, the entire account could be compromised & the reverse. If the main account happens to be hacked or compromised in some way, that malicious user now has control over every website on that account.

A reseller account would allow you to create 1 account for each website which can be managed by a "reseller". Each website cPanel account is it's own user with it's own permissions. This will aid in both security & performance.

However, the general consensus here on WF is to put as many addon domains on to HostGator "baby" account as you can. Those same people are here days/weeks later complaining about all of their websites being hacked.

With Hostgator "Baby" plan,you can host as many domains as you want.You can just add the additional domains as "addon" domains and unless you burn too much bandwdth,there shouldn't be any problem.