Need affordable prime lens

Thanks a lot, all of you. I guess I'll take a look a little bit more, and, since I'm not a professional, guess every lens with f/2.0 or bigger aperture will be good.

Now, there's one more thing. I said that my primary object is my kid while indoors, however, lens like this will probably be as good for outdoor picturing. And while taking pictures outside (portraits), some nice bokeh would really be appreciated. Is there any particular lens with especially nice bokeh, or any of mentioned will do good (or not)?

Regarding adapters, I will take a look a bit more. I guess adapter is not nearly as important as lens, but will definitely look for old discussions on that subject.