Where can I buy an awesome but affordable laptop in Nigeria?
You will probably need to do a Google search for local stores in Nigeria (if shipping is too expensive). If shipping is not a problem for you, then I think there won't be a problem with buying one online from major stores (like, Amazon).
For example, if you check Nigeria as region on alibaba.com you will have this: http://www.alibaba.com/countrysearch/NG/laptop.html
Also, check this one: http://www.mygadgetsmall.com/shopping/laptop-computers/cat_3.html