What cheap lens to buy?

Hi guys. I'm new to the forum and to the photography at all and that's my first thread, so sorry if there's allready the same debate.

Couple of weeks ago I bought myself an Olympus E-PM1 with the standart 14-42mm zuiko kit lens. I'm quite satisfied with the photos but I discovered that I'm a fan of the "bokeh" effect which unfotunatelly I can not get quite well with that lens. So my question is what lens will you recommend me. And my only requirement is to be cheap- not more than 50Eur. I browsed e-bay and there are many lenses for around 20-40eur. I read some reviews of different 50mm lenses and i really liked the minolta rokkor-x 50mm 1.4

So what can you recommend me?