On my 2004 trip I bought cheap camping equipment from one of the chain stores, and craigslist, and sold some of it on craigslist before flying home. The rest I donated to charity.
A couple of days before leaving home, I searched and found what I wanted, and arranged for settlement when I arrived in the US. Similarly I listed the items a few days before I was done, in the location from which I was leaving, mentioning the date it would be available. Definitely beats paying excess luggage.