You can try
Nexfan.com, they have the TMD fans for $4.99@. Both the 5800 rpm and 4500 rpm fans. They have a special right now that *SPECIAL* $6.99 FLAT RATE SHIPPING(UPS GROUND) UNLIMITED ITEMS!! I think you will find that almost all the on-line places charge about $8.00 shipping for small orders when using UPS or Fedex. If you can find a place that can ship by US mail, the shipping is around $5.00.
I have both of these fans and do not notice much differance in noise between them. After having the two TMD fans, I find nothing special or great about them compared to regular 70x70x15 fans but for $4.99@ you can see what I mean. I word of caution, do not tighten fan screws down. Just snug the screws down and do not over tighten. Use plastic mounting screws. They will strip out before you get to tight. If you overtighten the mounting screws, the outside metal cover on the fan can contact the motor coils and burn the fan up and more. Be careful.