Wilson shows in various ways that he cares a great deal about money. He might be called a miser. He hires John Clay because Clay offers to work for half the customary wages. Wilson doesn't even subscribe to a newspaper, which helps to explain why he had never heard about the Red-Headed League before Clay told him about it. Of course, there was nothing to read about it in the newspapers because it had never existed. But at least Wilson would have been suspicious if he had been subscribing to a newspaper and had never seen a word about it before Clay showed him the ad. Wilson is captivated by the idea of being able to earn four pounds a week just for copying articles out of the Encyclopedia Britannica, and he is devastated when the job abruptly ends. (This is a possible weakness in the plot. Clay might have been smarter to keep Wilson employed at the League offices for a little while longer, rather than posting that notice that the League had been dissolved before he had gotten his hands on the French gold.) Wilson comes to Sherlock Holmes with his petty problem because he has heard that the great detective sometimes takes cases on a pro bono basis if they interest him. Wilson is actually hoping to get the services of the famous Sherlock Holmes for nothing. It is quite true that Holmes takes cases free of charge if they interest him, and Wilson is lucky that his case interests Holmes very much because he sees that there must be something of extreme seriousness behind this so-called Red-Headed League.
It is a little difficult to understand exactly why Jabez Wilson comes to Sherlock Holmes and what he hopes the great detective will do for him. Wilson has only the very faintest hope of regaining his post at the Red-Headed League with the extremely welcome four gold sovereigns every week. The author, Sir Arthur Conan Doyle, must realize that this is a rather sticky wicket to get through in plotting his story, so he has Holmes himself bring up the same question many readers would ask.
"On the contrary, you are, as I understand, richer by some £30, to say nothing of the minute knowledge which you have gained on every subject which comes under the letter A. You have lost nothing by them.”
“No, sir. But I want to find out about them, and who they are, and what their object was in playing this prank—if it was a prank—upon me. It was a pretty expensive joke for them, for it cost them two and thirty pounds.”
So Jabez Wilson mainly wants to find out why the man named Duncan Ross and whoever his associates are have played a prank on him and made him feel like a fool for spending eight weeks copying the detailed information in the Encyclopedia Britannica. He obviously doesn't like people laughing at him. His blazing red hair has made him hypersensitive because kids probably poked fun at him in school and he has been the butt of stupid jokes for most of his life just because of his red hair. When Holmes and Watson laugh at him earlier, he flares up:
“I cannot see that there is anything very funny,” cried our client, flushing up to the roots of his flaming head. “If you can do nothing better than laugh at me, I can go elsewhere.”
The fact is he cannot go elsewhere because he is trying to get an expert to help him for nothing. Sherlock Holmes is his only hope--and yet he risks alienating him by losing his temper. It is because he was fooled by pranksters who used his red hair for the purpose that Wilson is sufficiently outraged to want to track them down. Everybody has an Achilles heel, and Wilson's unusually brilliant red hair is his. Perhaps he did not intend to ask Sherlock Holmes to go out and investigate the case for him but only to give him some free advice. Holmes hasn't committed himself to doing anything except to listen to Wilson's story until the detective senses that there must be something much more important to the matter. Earlier he tells Watson:
As far as I have heard, it is impossible for me to say whether the present case is an instance of crime or not, but the course of event is certainly among the most singular that I have ever listened to.
It seems likely that Holmes would not have gotten involved in Wilson's case at all if the detective hadn't suspected that it was indeed "an instance of crime."
Jabez Wilson seeks the help of Sherlock Holmes because he has had a strange experience. He was hired by something called the "Red Headed League" for simply having a nice shade of red hair. He was paid a good amount of money to do nothing more than copy an Encyclopedia for some fixed hours every single day. One day, he arrives at the office in which he works to find the door locked and a note that the league has been dissolved. Wilson wants Holmes to find out what this whole incident was about and where the Red Headed League disappeared to.
Something else worth mentioning is that it's true Wilson is a money-minded man. He has modest roots and makes his living from his store which doesn't give him the best standard of living. Holmes is aware of this. In fact, Wilson's store is roughed up when Holmes and Watson catch one of the thieves. The owner of the bank gives Holmes a sum of money for catching the thieves and preventing the robbery of the bank. Holmes in turn gives some of the money to Wilson. Wilson returns home quite content with how things have turned out.
Wilson finds a sign on the door of the office where he'd been working for the league. It reads as follows:
"THE RED-HEADED LEAGUE
October 9, 1890."
He comes to see Holmes because his unexpected benefit (the league) is gone, because he doesn't know why, and because it is a mystery.