Help me choose the right home machine

I am getting ready to have the RNY in January and I have about $500.00 to spend for a home machine. I am completely new to this and really need  your help.
My husband would like to have a Treadmill and I want an elliptical. Do they have one that does both? probably not... so lets move on...

I AM having the surgery and I HAVE the money so elliptical it is first... I am 317lbs so the max weight is a factor...
Play it again has an elliptical Schwinn 418 in my price range brand new... do you recomend it or if not what would you recomend? Please keep in mind my price range.

Thanks a bunch for your input. Trying to get it before christmas.

I have a Bremshey rear fly wheel which I really like but I REALLY want a Tunturi E300.
http://www.allellipticals.com/endurance-e300-elliptical.html

You really need to test drive a few before you buy as they all feel different and what may feel alright for someone else may not feel right for you.  I think I tried about 30 before I found mine and I had it narrowed down to 3 ellipticals.

 A couch to 5K program can be found free or under $10.00. All you need is a pair of sneakers. Just saying instead of spending a lot of money on something too soon to really know what you would like long term or maybe not knowing what your ultimate exercise goals are the program gives a way to really get going.

Just a thought. Lots of people on this forum have used the plan, and then moved on to other specific training equipment once they understood what they wanted fro their exercise.

Good luck.

Have you considered looking on Craigslist for a used one?  You could probably get an elliptical and a treadmill for $500 if you get used ones.  People buy then and then don't use them.  In my area there are tons of posts on Craigslist daily. 
I have an elliptical in my basement, but I never use it.  It was about $700, but it's sort of squeaky and wobbly. 
I just joined Planet Fitness a few weeks ago and I'm really liking it.  I like it much better than working out at home.  Gets me out of the house so I get a break from the kids. Plus there are so many different things to choose from and you can also get in some weight training in addition to the cardio.  If you have one near you, you may want to consider it.  My membership is only $10/month. 

Congrats on planning your exercise and having surgery!

Personally, I would not invest in home equipment before you are sure you will even use it.  Trying out a gym for a few months (and maybe you have) would be smarter, since you might find out you really like biking, or would rather a treadmill or stairmaster.  Also, it's much easier NOT to exercise when it's right there in your house.  Sounds counter-intuitive, but the majority of exercise equipment in homes is used as a clothes hanger.  speaking from experience here. 

Now I just run/walk outside. even in the winter.

 I used an elliptical for the first 3-4 months in my house after surgery.  I was a lot more comfortable as a large dude in private and it allowed me to be on a rigid schedule.  That said, as my weight came down, I started a couch to 5k like program running outside, and then joined a gym.  I never touched the elliptical in the house again (its been about 2 years now).  

My suggestion would be craigslist, but have a goal of eventually not needing it, and wanting to be in a gym and on the road.  I like the gym because you can work differently every day.  When you only have 1 machine at home, its tough to do the same thing over and over.  

Definitely get something used. Most people don't use their home machines much so getting one for less is a good idea. Then, if you turn out to be one of the people *****ally does use it, you can use the money you've saved to get even more home equipment!