I LOVE costco fresh tortillas. They are indeed a revelation. I am also a 1 person tortilla eating household, and I manage to eat all 50 before they go bad. Tips:
1. Freeze half. I know it says not recommended, and the first half is a tad better, but they are still pretty damn tasty after being frozen.
2. I know it says that once you open the package of 25, you have some insanely short period of time in which to eat them. That is a lie. They are tastier/fluffier/cook faster at the beginning, but I've taken a full 3-4 weeks to finish a package and the last ones are still totally delish.
3. If you worry you're pushing it, cook up a bunch at once and put them back into a zip top package. Ta-da! You have a new package of pre-cooked tortillas.
4. Don't use the zip top package they come with. The plastic around the zipper breaks very easily, and the zipper itself is impossible to open, so unless you're much better at these things than I am, it won't really have a good seal.
5. Cook up a bunch (like 10), make a pan of enchiladas, put it in the freezer to thaw and bake later.