You want the best? Are you sure?
http://uk.rs-online.com/web/p/ohmme...eproducts-_-FeaturedProductsContent-_-6718864
Measure the resistance of your sub-ohm coils accurate to within 0.0004 ohms, (beating the Fluke by a wide margin.) Automatically compensates for lead resistance.
A steal at only £600 (about $900).
For voltage there's this one:
Buy Digital Multimeters RSCAL(2333251),TTI 1705 bench multimeter Aim-TTi 58122-0640 online from RS for next day delivery.
With 12,000 counts it will measure your battery voltage accurate to within 0.0016 volts and calculate the true RMS power that will be delivered to your coil no matter what strange waveform your mod puts out.
Yours for only £478 (about $650).

-Darn you brits and you pounds, always get's my hopes up when I look at prices! I plan on visiting liverpool soon.