John Lee Ball Jr. says that he plays the "musical saw," walks 20 miles everyday and used to sell ice cream on 15th Street in Washington.

John Eugene Selliner actually lives in Oxon Hill but says he likes to use a Fort Washington postal address because "it sounds more authoritative."

Vincent Goodsell spent 34 years in the Army before he retired, moved to Laurel, and went into business as a philatelist.

County Executive Winfield M. Kelly Jr. has a campaign chest of nearly $200,000, the power of incumbency and the support of a political machine unrivaled in Maryland. Goodsell, Ball and Sellner-who are challenging Kelly in the Democratic primary-admit that their campaigns consist of little more than their own thoughts.

On some matters, Ball's thoughts are uncertain. When asked whether he supported the Proposition 13 style referendum in his county, he responded, "Give me a fortnight to sleep on this." On other questions, however, this 48-year-old son of a former county sheriff is quite clear. He believes that Kelly and the police have not treated the county's black community properly. "And I'm white," he adds.

He also believes that Kelly has not provided enough housing or jobs for moderate-income and poor people.

Ball has used less than $100 in his campaign. His major expense has been his filing fee. Last week, when he was getting a ride from Goodsell after a television taping, Ball told Goodsell that he probably would not have run for county executive "if I only knew you were going to." The week before, Kelly encountered Ball's sister, an old high school classmate, on the street.

"I'm sorry, Mr. Kelly," said Ball's sister to the county executive. "None of us know why John's doing this." Ball is ready and willing to tell anyone why he is running against Kelly. It is often hard to reach him, however. His telephone number is unlisted.

Sellner's thoughts center on one thing and one thing only. For years now, he has been trying to get law enforcement authorities to listen to what he has to say about what he believes was a massive murder conspiracy in the county involving relatives of a former chief of police. Sellner has "bushel baskets" full of documents, he says, that substantiate his story.

But the state's attorney would not listen to him. The County Council would listen only politely. And Winfield Kelly would not even do that. The last time the two men met, at one of Kelly's monthly "open door" sessions with people who walk in off the street, Sellner got in line for an audience with the county executive.

When his turn came, the pleasantries were brief. The conversation was not going anywhere. Said Sellner to Kelly: "It looks like one of us is going to have to shove off." It was Kelly who shoved off, taking the elevator back up to his fifth floor office.

When the 48-year-old Sellner is not talking about his murder conspiracy theories he likes to discuss human rights and trash pick-up. He believes that there are two human rights standards in Prince George's County, one for the politically-connected and another for everyone else. Sellner says he ought to know about such things-he was a county policeman for more than 20 years until he resigned in 1974.

As for trash collection, Sellner thinks all county refuse should be transported to a railyard near Upper Malboro, where a recycling plant should be built. Some of the waste, he thinks, should be taken to a cool plant; the rest to Baltimore.

Vincent Goodsell, a man of the world at age 62, has a somewhat broader scope of interest than his two fellow candidates in the race against Kelly. He also has more support and money. The support comes from senior citizens, whom he worked for in the county Department of Human Resources until Kelly reorganized his job out of existence last year. It also comes from a group known as AID, the Alliance of Independent Democrats, a coalition of insurgents challenging the dominant Democratic organization which Kelly leads.

As far as money goes. Goodsell has about $5,000 in his campaign treasury, three-fourths of which came from his own pocket. Goodspell spent a good chunk ofit last week when he had 2,000 grocery bags printed up with "Goodsell for County Executive" on one side and "Venetoulis for Governor" on the other side. He gave the bags to senior citizens at their annual picnic.

This is Goodsell's first attempt at public office. He is running, he says, because what he saw when he worked under Kelly for three years left him "dumbfounded." He saw "waste, a lack of management, and a lack of concern for seniors and others who need assistance."

Goodsell describes himself as a "center of the road" candidate Kelly, he says, is neither to the right nor the left of him, but "wherever opportunity knocks." He calls Kelly a "fairweather friend" who believes in tax relief only during election year and the rest of the time asks people to pay apartment taxes and telephone taxes.