When I was 13 a mate and I made one out of a couple cardboard tubes that could slide together. Had a 1 dioptre lens from the local optometrist for the front lens and a standard magnifying glass as eye piece. Could see the craters on the moon and saturn rings with that.
you don't need much to see rings of Saturn, moons of Jupiter and Venus and Mars as crescents, (if they're not full).
I've since bought an el-cheapo 700mm Tasco, about the most basic I could by at the time, and that does that no worries, I made an adapter to fit my first digital camera to it and took some pics.
Taken the same night but they were much further apart than this, I've copy pasted Saturn into Jupiter's pic, which has 3 moons showing. Getting the exposure just right is tricky, if you give it enough exposure to clearly show the moons Jupiter is too bright to show the rings, this pic does neither well, it's a compromise to show both.
Through the eye piece the human eye has no trouble seeing both, and doesn't have to cope with my dodgy camera adaptation.
And here's the moon through it.
The main thing wrong with the telescope is the cheap mount, it's no where near balanced, and the brake has to be on quite hard to stop it moving, so trying to track a moving planet gets jerky. I've added about 1kg of lead to improve the balance and make the movement smoother. It's also got a sloppy focussing movement, I've added mylar shims around the tubes so the eye piece doesn't move about so much.
A few years ago now we went to the Gin Gin observatory, and were quite disappointed, their very expensive much bigger telescopes didn't show much more than we could see through ours. I guess we've just been spoilt by those lovely Hubble pictures.
Oh yeah almost forgot, here's the McNaught comet.