I recently bought 2 sets of letter sprues and a maulerfiend sprue from Bitzbarn.
2 x Bloodletters $57NZD, 1 Maulerfiend $105NZD = $219NZD Retail from NZ GW, however I got them from Bitzbarn for $141 NZD post included charged to my Visa Debit. that's a 36% saving including postage. Now the bitz service is 20% all GW stuff and with exchange rates (GW still focused on 90's exchange rates for NZ and Australia).
Vagabond is good if you need them in the next day or so.
Now I haven't got an aunt in the US(but my wife does) however NZ Post's Youshop offers a USA mail address for honest resellers. I haven't tried it but it seems good to avoid illegal regional protectinoist practices some companies use.
There is great stuff on trademe and ebay. For overseas stuff you have to watch what they charge for international shipping. Apparently some of the stuff they get hookers to transport it some of the way. I managed to pick up all my old Tzeentch stuff from ebay and all 4 greater Daemons, 40 old pink and blue horrors, plus 7 old Lords of Change for under $200 NZD. You just have to be patient. Sometimes if you bid on whole lots like people having a clean out they will have some superb stuff. On one lot auction I managed to get for $80NZD approximately $1500NZD worth of Miniatures on one trademe bargain. You just have to keep your eyes peeled and examine each picture in the somewhat bad descriptions to know what you're looking for.
Theny there are alternate miniature manufacturers like Mantic and Avatars of War shipped from S2P. I use these because they have cheaper and sometimes better miniatures than GW. As a consumer of Minature Wargaming I have a choice.
I've saved money too lately.
Now from Bitzbarn I don't get the pretty boxes they come in, but who cares.