We just put in a big order through Mouser for ours. We haven't received our order yet but I assume they will be fine. If you look up the exact part numbers and order in large quantities they were the cheapest I was able to find. You can also order what ever color you want as well, we are moving to purple and white this year.
45 Amp Tin Contacts $0.105-$0.15 (Tin contacts are rated for fewer mating cycles but we rarely put over 1,500 cycles on any of our contacts)
Red Housing $0.201-$0.33
Black Housing $0.202-$0.38