Search PowerWerx on Google. I dont have enough posts to put the URL down...

$50 for the 150 piece kit or you can buy them separate starting from like $9.

Make sure you get the "tool" that they offer. Its $30 and called the TriCrimp. Its amazing and worth its weight in gold.

The 30 amp connectors are good down to 12 gauge wire. The 45 amp are good down to i think 10 gauge wire. I run the 30amp on mine since Castle, Traxxas and Trackstar ESC's use 12-14 gauge wire. 15-45amp versions all use the same housings also so it makes them all compatible with each other.

Only gripe so far is that they are a tiny bit bigger than a TRX connector. Using them on some of my smaller models has proven to be annoying(under 1/14 scale). I do fine with them its just annoying cramming everything under a 1/14 or 1/18 scale buggy body.