The collectors consist of four fish: two that are unnamed and the other two being Nat Peterson and Fred. The first fish is the unnamed male who offered up $500 for Mr. Krabs' soda drinking hat. The offers continue to rise until Fred offers up one million dollars which leaves Mr. Krabs running back to SpongeBob in his own saliva.
The collectors are not seen again until the end of the episode where Mr. Krabs is ready to sell his soda drinking hat for one million dollars.
The collectors laugh at him and Nat ends up telling Mr. Krabs that they found a whole warehouse of soda drinking hats and that it is totally worthless and points to a dumpster full of soda drinking hats. The collectors then spot SpongeBob with a clapping hat and then chase off after him, wanting to buy it. Even the female collector offers to give SpongeBob one billion dollars for his new hat. Mr. Krabs is highly upset and cries with Squidward saying, "What a baby."
Oddly, the male collector was not seen in the group when Fred first came up offering one million dollars to Mr. Krabs. It is possible he heard about the hat, after Mr. Krabs left.