Bricklink is fantastic. I usually pay through PayPal when I buy on there, and I haven't really had any problems with the site.

If a problem does arise with a particular seller, try to communicate to them and see if they will refund you or send a new piece for you. Giving negative feedback before discussing problems could lead to negative feedback for you, and usually store owners are very accomodating (at least, in my experience).

Hope that helps!

Bricklink is a great resource, it's definitely the most reliable place to buy specific parts- unless, of course, PaB, by some miracle, has what you want. Like Ebay, it is individual sellers, but I've yet to encounter a bad one. Most of the people genuinely understand and care about Lego, so you shouldn't have any problems.

My only suggestion is to be mindful of sellers that indicate the parts will be coming from a smoking home, and to ask before purchase if they don't if it's enough of a concern. My one bad experience was when that wasn't indicated (and to top it off, the Vahi came bent...). Besides that, it's a great place.

Bricklink is pretty rad. Make sure when you do your searches for parts that they have the number of pieces you need though! I have had ones where I find someone who has the parts I need for super cheap, but then they only have 5 available when I need 50.

Keep an eye out for ones that need a minimum purchase, as sometimes you can find sellers with everything you need, or you can find multiple with no minimum purchase.

Also, if you only want to purchase from inside your home country, make sure you have your searches set for that, because sometimes if your order from a seller outside of your country it takes forever, so if you're in a time crunch, only order in your country. DeeVee has bought Bionicle parts from Germany and they show up weeks later and he'll be all "wait, I bought parts? Oh yeah, that was like, a month ago, I forgot".

Thanks everybody! I have everything I need in my wanted list now, but I still need some help. I am trying to find out where to buy them from. I can't find a way to see how much a store has of my wanted list without going into it, hitting the "Show all Items this Store has in your wanted list" button and hoping for the best. Is there any way to sort by the amount of your wanted list a store has in the search? I need like 16 different pieces, and every store I look at has like two of them.

It isn't like I need anything particularly fancy either, I mostly need pins and axles, and some various Technic pieces. All in, like, black too. So they aren't rare pieces or anything. =P

E: Oh wait, I just found it. Comparing things now, unfortunately not even the top result has everything. D=

When you're searching for a piece, you can sort from most to least pieces available in a store. I know I sometimes use that when I only need say, 20 of something, and I just scroll down until I find a store with close or exact to what I need, depending on if they have a minimum purchase requirement.