Even superior telescopes will produce disappointing views with a poor eyepiece. The good side of this is if you have a reasonable good quality scope putting a good eyepiece in will make all the difference in your viewing pleasure. You may even find it hard to believe your looking through the same telescope. Most hobbyists carry a set of eyepieces with them, switching out according to the task. The sacrifice is a reduction in brightness and field of view.
Low power yields a wide field and brighter objects.
Purchase only 1.25 inch or 2 inch diameter eyepieces. You must see to it that you purchase only scopes that take either or both of these sizes. If you already own one of these eyepieces you should see if it could be changed over to fit the 1.25-inch size. Zoom eyepiece are not recommended. There are several design types available.