Wholesales 10pcs C3 4 ER20 1 38 Straight Collet Chuck Holder CNC Milling Lathe | eBay

Try this link, the site shows that its an active listing.

They dont always have all sizes available but usually er11 and er20.
I use the er20 and er11 varieties, no problems with excessive runout.

I also bought some Chinese endmills, the ad says they are good for wood or aluminum, I have about 3000 wood blocks to make and I didnt want to ruin expensive cutters on them, so I bought 10 just for a test. They work suprisingly well, the edge seems to last as long as a HSS quality cutter, they were less than 20 dollars for 10 of them delivered! They are 3 flute 6mm and not center cutting, but on wood that doesnt make much difference in my application.

Acids in the wood destroy the sharp cutting edge quickly, carbide or HSS if the wood is not very dry, but at this price just replace the cutter.

6mm x 6mm 3 Flute HSS Aluminium End Mill Cutter Extended CNC Bit Sale - Banggood.com