Replacement keyfobs

Both of our remote keyfobs for our 2001 Lw200 has ceased to function.
The metal clip holding the battery has broken on both.

Two questions, how compatible are the different keyfobs? I found a seller
on eBay with three fobs that look similar, same buttons, but different
housing. Will they be able to be programmed to work?

Second, we are stuck with reprogramming them without going to the dealer
since we do not currently have a working keyfob right?

 

There is a GM code number on the back of each key fob that must match. They
need to be the exact type as the orig , so that different size is for a
wrong Saturn. Most saturns of that model and yr will have that code. Yes,
you will need to have both fobs and the car taken together to the dealer for
them to program, but it isn't very expensive.

 

I think the fobs cost about $80. Should the fob die because of the battery
alone, there are instructions on the inside of the battery cover telling you
how to approach your car.