Free advice:
Don't get robbed by a watch parts supply house unless you are in a hurry.
Look in the phone directory and see if there is a tool, bolt and screw specialty store in town and call them about the taps. I bought the taps 5 for $25 from a tool/screw shop. They were PRO-CUT brand, very good quality.
If I bought 25, they were $4 each. Five was enough...
Amazon also has 3.0 x .35mm tap sets for $21.30, free delivery. "Includes 1 each: Taper, Plug & Bottoming Tap."
https://www.amazon.com/3-0mm-35mm-Tap-Set-Sets/dp/B00M89XOOA/ref=sr_1_1?s=hi&ie=UTF8&qid=1522862462&sr=1-1&keywords=3.0mm+x+.35mm+metric+tap
Here they are for less than $4 each including delivery:
eBay item number 231977555390
Here is an explanation of the different types of taps:
https://en.wikipedia.org/wiki/Tap_and_die
'Plug Tap' is usually the type needed.