I'm a machinist and I buy titanium occasionally, it is not that expensive, it retails around $35.00/lb. so wholesale has to sell for less, and you can make at least five nails or more with a pound.
Having said that, I don't know if the Chinese are using pure titanium, if you ever want to take the risk it is very easy to find out the purity of it, just find a large recycling plant in your neighborhood and they'll tell you whether it is pure or not, they should have hand held equipment for that.
And about G2 being superior to the other three pure grades, don't buy into the hype, all four grades are good, there's less than 1% difference between them, so my question is this: what makes G2 better than G1, if purity is a factor them G1 should be a better choice, don't you think?
Don't have to answer the question, this should be asked in a different forum, just wanted to state my opinion.