Larger lenses or mirrors are much more important than large magnification. Telescopes below about two inches in diameter are not very useful. Three inches and up is much better. The astronomy magazines carry numerous advertisements for good telescopes. You might find a used one for much less.
Astronomy is a wonderful family activity.
It's a subject you can explore completely on your own, with no previous experience necessary. Children of all ages can be involved. Go exploring as a family and learn together. Discover the excitement of astronomy. Bill Lovegrove has a B.S. in physics and a Ph.D. in computer engineering.