I have been able to get a few of them from a player by asking to purchase them for face (for the $25 and $5) if they were at the table going to play them. its better for them and I get to add a chip to my NCV collection. I've been able to get a few of them that way. But you have to be in the right place at the right time. Otherwise they would play the NCV-25 chip and if they win they get $25, but if I buy it and they play the $25 and win they have $50. Once you explain that they will sell it willingly. I've even bought them for less

I've also been invited to get some at different casinos as well. Stations casinos often have contests where the winner will get one or more of the chips (depending on the contest) and I have been able to get a few that way as well.