I'm going to buy an AF 50mm lens for my Nikon D3300 because I do not have money to buy an AF-S lens. I plan to use it with manual focus. Will it be worth it and give good results ?
Digital camera viewfinders don't have the special focusing aids film cameras had to make manual focusing easy. 50mm is a bit long to try to focus manually with a flat glass viewfinder on a crop sensor camera that lacks DoF preview, especially if you're buying a prime with the intention of using large apertures (which reduce depth of field even further).
If you were shooting landscapes with a 14mm lens and a distance scale or had a viewfinder meant for manual focus on a DSLR (KatzEye for example) then you would be okay, but starting off with a D3300 and a manual focus 50mm lens might make photography less enjoyable.
I recommend the 35mm f/1.8 G AF-S or 50mm f/1.8 G AF-S. Make sure you consider your camera's crop factor before choosing 35mm or 50mm.
Based on my practice, when I shoot with my 50mm I use more often the auto-focus than when shooting with other lens. That is why I think that AF-S is more suitable. I also have d3300 and use the AF-S 50m and the results are awesome.
The AF-S is no more then 80-100 $ more expensive. I think that this is not so much for a good lens.
Both, AF and AF-S are very good lenses for their price, but I believe that the nature of shooting with 50mm is demanding to use auto focus more often.
It is up to your decision. But you may struggle to focus properly on manual