You could always do what I do.
Keep a list of parts you need (in a text file, or on your wanted list on bricklink) and wait until you have enough pieces to make an order.
I buy random lots on a regular basis and use this method to finish sets.
Also - Don't feel overwhelmed, bricklink is as easy as buying something on ebay. You buy your item/items, pay, receive, verify, leave feedback. I was a bit confused the first time I ordered, but the anxiety wore off quickly :)