tax id's are easy to get, most states have a webiste that you can do it all online.. ie florida has sunbiz dot org. you can pay all your taxes right there online too. I believe it's ~$130 to register. It's a good idea to have, it can protect you if many ways. you dont get sued... your company does, which as far as the law is concerned you and your business are different entities. plus you can get shit at wholesale
if you are creating an LLC... just make sure you put 'LLC' in the name of your buisness, or it wont go through.. ie 'The Best Buisness Ever LLC' is the full name.