Medicare open enrollment begins on October 15,2013 and runs through December 7, 2013. October 15, 2013 you will be able to see all the plans available in your zip code for Medicare Advantage, medigap and part D prescription drug insurance on www.medicare.gov. These plans will have 2014 prices. Medicare will also publish the part B premium for 2014. All of this is important information for you to have so that you can make the best choices based on your subsidy.
Medicare.gov is the only authoritative source for those prices. Don't rely on any other site for insurance company premium prices. I have seen several chat room postings that include premium prices. I doubt they are 2014 prices since insurance companies don't have to release those prices until Medicare open enrollment. There is also a lot of misinformation floating around about medigap plans so I wrote a lot more about medigaps in this post.
The rules for medigap plans are different from state to state so you must find out the rules for your state. Call your state health insurance assistance agency to find out the rules and the prices (go to www.shiptalk.org to get the phone number). Specific company medigap policy prices are not on www.medicare.gov - the site only gives you a price range. Also, on medicare.gov to find medigap information you have to go to the top of the site's homepage. Medigaps are not included in the "planfinder" link in the middle of the site's homepage because you cannot directly enroll in medigaps off of medicare.gov. You must contact the insurance company to enroll. It has also been my experience in helping people that insurance companies do not like to sell low premium medigap plans and make it difficult to buy one. They will try to upsell you. In that regard, Extend Health will be great as they do the enrollment for you if you buy through them.
As I said, the rules for medigap widely range from state to state. New York is fabulous when it comes to medigap plans. First, there is no "enrollment period". You can enroll in a medigap plan any time you want and you can change from one type of plan to another whenever you want. How this will work with Extend Health enrollment is not clear. I did ask EH but the agent didn't even know NY had continuous enrollment. You do not have to previously had a medigap plan to get a medigap plan so there is no "guaranteed issue" problem. NY has what is called continuous enrollment. As I said, there is no requirement to have had a prior medigap plan - however if you have a preexisting condition an insurance company is allowed to delay covering that condition for up to 6 months. Most don't but it is important to ask. The Affordable Care Act does not have any affect on secondary insurance regarding pre-existing conditions so the medigap plans are allowed to do it.
New York also requires insurance companies to do community rating for prices. That means no matter how old you are your premium is the same as everyone else in the plan - it is based on where you live. I don't know how they decide to set community prices but will guess it is based on demographics, physician prices (doctors are allowed in NY to charge up to 5% more than the Medicare fee for most procedures and 15% more for a small subset of procedures) and hospital pricing. It is well known that hospitals charges range widely from one to another.