Just listing a source of PCB related micro endmills, drill bits, engraving v-bits and various other types.
Store page: http://stores.ebay.com/carbideplus/
Most of the bits are Kyocera Tycom brand, normally sold into the printed circuit board market and made in the USA.
Shipping options (combined for multiple items):
$3.45 1st class mail
$7.05 priority mail - includes 50 pack storage box ($5 on its own) http://www.ebay.com/itm/50-PACK-STORAGE-BOX-ORGANIZE-YOUR-SMALL-TOOLS-/381467824946?hash=item58d1411332
Listed on the Shapeoko wiki (as well as other sources): https://www.shapeoko.com/wiki/index.php/Endmills#Specific_Bit_and_Brand_Recommendations