Well i've bought a cheap prime lens from eBay its for my canon and its a pretty cheap lens as new so it only cost me around £50, i borrowed one from a friend and was really surprised how good the Little feller was. Focusing was super quick and it was a lovely lens to work with in low light situations as it has a really low F stop of around 1. something compared to that of my stock lens which is 3.5 i think. It's a 50mm so quite close but if your not needing a zoom lens then its a great lens and will do a great job at portraits too. The hardest thing to get familiar with is the fact that there is no zoom ring so you phsyically need to move forwards and backwards.
Hopefully i can get some pictures and post them up