One inch wouldn't really hurt anything when it's just getting you to the tire store.
I would not recommend "daily" use of a mismatched spare. Reasons are:
1. If you have a locker on that axle, using the tire will destroy the locker.
2. If you have a limited slip on that axle, you will probably destroy it (or at least wear it out much faster).
3. If you have it up front, your alignment will be gone and your tires will wear much faster and the vehicle won't want to track nearly as well.
4. If you hang it in the rear, the handling of the vehicle (especially in hard/emergency braking situations) won't be great either.
Or, the short version is: Buy a new tire to replace the bad one now and get a same size spare when you can. Some places may trade your "good" spare for a not quite so good tire for cheap/free or search crapslist/ebuy.