I am currently building a new single speed bicycle and want to swap out the crankset for asthetic puposes(the one currently on the bike has an ugly ring around the chainrings). Ive been browsing around ebay looking at cranksets and noticing they are not that expensive. Could someone tell me if there are other parts I am going to have to buy besides the arms and chainring? I was also wondering the complexity of the task. Please respond with any tips or though on the matter.

Thanks