John B. Anderson, previously unable to afford any television or radio commercials, today announced plans to launch a $2 million advertising campaign next week, financed by thousands of small loans from Anderson supporters.

Unsuccessful in attempts to borrow money from banks, Anderson turned for loans last week to people who had previously donated money to his independent presidential campaign.

In a letter sent to 185,000 households, Anderson promised to repay the loans with 8 percent interest. He promised to use federal campaign funds he hopes to receive after the election.

"Banks just aren't in the business of staking political races, especially for a peoples' campaign," said the letter, mailed Sept. 29. "Even if we're lucky and get one or two loans they will not be enough to meet our enormous needs."

Returns from the mail appeal began showing up this week. On Monday, the campaign received $87,000, on Tuesday $200,000 and on Wednesday $120,000, according to press secretary Tom Mathews, whose direct-mail firm also handles Anderson accounts. The average loan was for $85.

Based on these returns, Mathews said the campaign expects to raise $1 million by next week.David Garth, Anderson's campaign director and a wellknown media expert, today began preparing a new series of radio and television ads to be broadcast beginning next week, he said.

The campaign today sent out a second batch of loan appeals to 17,000 people who have donated $100 or more, inviting them to become members of Anderson's national finance committee. To qualify, they are asked to lend the difference between the amount they have already donated and the $1,000 federal limit on campaign contributions.

Eight hundred test letters similar to this raised $60,000 in one week in Massachusetts. Based on this, Mathews estimated that Anderson will be able to raise from $500,000 to $1 million.

"This means we will have a total of about $2 million from a new source he hadn't planned on and we'll be on the air next week with radio and TV," he said.

Garth is preparing a series of five-minute televison commercials and a 30-minute network program to be broadcast in the closing days of the campaign.

The $2 million figure is still considerably less than Anderson had hoped to have for an advertising budget. After the Federal Election Commission ruled on Sept. 2 that he would be eligible for retroactive government campaign subsidies if he recieved 5 percent of the vote or more, Anderson said he hoped to get bank loans of up to $10 million. But he has been unsuccessful in getting any such loans to date, although the campaign continues to seek loans of about $1 million from some banks.

As nominees of the Republican and Democratic parties, respectively, Ronald Reagan and President Carter each automatically received $29.4 million in federal campaign subsidies. They have allocated about half that amount for advertising.

Anderson, who campaigned in Connecticut and Ohio today, has blamed his recent drop in national public opinion polls on his inability to afford any advertising.

In an early morning speech at the Yale University law school in New Haven, the candidate accused the "Christian Right" of injecting "a new bitterness and absolutism" into American politics and reopening the religion issue that John F. Kennedy's election in 1960 was thought to have put to rest, Kennedy was the first Roman Catholic to be elected president. The Christian Right, Anderson said, "threatens our historic and constitutional separation of church and state."

Later, Anderson, appearing before a crowd of about 1,500 outside the headquarters of the Nationwide Insurance Co., used a number of insurance slogans to boost his independent candidacy.

"I don't suppose I should say, standing where I am today, that you would be in good hands with Anderson. That sounds too much like your competitors -- Allstate," he said. "Nor should I suggest we are the rock of all political candidates in 1980. That's much too Prudential. But I will tell you, that as independent agents, we will be for everyone and we will give everyone the best deal possible."