I wouldn't trust a DMM below 1 ohm. I wouldn't trust an ohm reader from eBay unless I'd calibrated it myself with known resistances, but if I had, then it's going to be accurate enough. It's all about Full Scale and accuracy. A DMM might be accurate to 0.1% of full-scale, but full scale is generally 200 ohms. That 0.2 ohms will bite you hard below 1 ohm. The ohm meters are generally accurate to only 1%, but their full-scale is much lower, maybe 3 ohms or 10 ohms.
Even so, I wouldn't trust them to read a 0.06 ohm nickel coil. For that you need a wheatstone bridge and even then the contact resistance of the 510 connection will vary between the meter and the mod by enough to throw your measurement out.
The only physical property that is usually measured more accurately than 0.1% is time. Generally you can throw together something cheap that will get 1%. Good attention to detail will get you to 0.1%. Getting any more accurate is significantly difficult.