Help me buying a telescope.?

Nothing will destroy a budding astronomy hobby like a small, cheap refractor. The 50mm objective lens is the same size as one of my binocular lenses, and probably much worse quality. If you don't have the money to buy a real scope, not a toy, get some binoculars, like some 7x35s or 7x50s. I have several nice telescopes and I still spent alot of time with my binos, looking at wide field views of the sky. They are ideal for learning the constellations. If you still want more, look into a reflector with at least a 150 to 200mm main mirror on a nice simple at/alz mount like a dobsonian. Not sure what you options are in India (right?), but look for a respected brand like Meade, Celestron, Orion, GSO, Skywatcher, etc.