A common simple refractor design is a 100 mm doublett lens with a focal length of 1000 mm. For maximum FoV you'd need a 50 mm eyepice. Together with a 2xbarlow lens and a second eyepiece around 12 mm. This way you'd get magnifications of 20, 40, 83 and 167.
I'd recommend that you start by getting your hands on a book on building telescopes and checking if there is an amateur astronomer club nearby. There are a lot of gotchas if you haven't built a telescope before.