Experts say that the cost of anti-retroviral drugs used to keep AIDS at bay will keep falling because of the demand from millions of sufferers desperate for the lifeline.
But nations still wrangled ahead of a major three day AIDS summit over how many people will get treatment in coming years.
The summit of about 30 presidents and government leaders must set the future direction of global AIDS policies. Pop stars such as Alicia Keys and Annie Lennox joined pressure groups in demanding rich nations pay the money needed to treat millions more sufferers.
The market economy will drive down the prices of the retrovirals used to keep millions alive now, according to Morolake Odetoyinbo, a board member of the Global Fund to fight AIDS, Tuberculosis and Malaria from Nigeria.
The cost "can only keep falling because they are trying to get more people on treatment, which means there is a bigger demand and that big demand will drive down the prices," she told AFP.
Odetoyinbo, founder of the Positive Action for Treatment Access group in Nigeria, stressed that it was imperative to reduce the cost of treatment to get more people onto the life-saving drugs.
There are an estimated 34 million people living with AIDS and more than nine million are still not getting treatment, according to UN statistics. About 6.6 million people are getting drugs and the rest do not know they have AIDS.
The annual cost of retrovirals was about 10,000 dollars in 2001 but has tumbled to about 67 dollars a year, according to Sharonann Lynch, an expert for the Medecins Sans Frontieres, or Doctors Without Borders, group.
"Cost is unfortunately the over-riding factor in terms of whether indeed we will be getting the remaining nine million people on treatment who need it today in order to live," Lynch said.
"The question of cost is so important that it's actually driving poor decisions in terms of whether governements participating will take the necessary steps and make the necessary financial investments so that we can finally break the back of this epidemic," the expert said.
Going into the summit, no agreement had been reached on the final communique which was to set the numbers who will receive treatment and how it will be paid for.
The UN Security Council on Tuesday passed a resolution calling for a coordinated international response to the AIDS pandemic, which it said was a threat to international peace and security.
But pressure groups said rich countries -- Europe and North America -- were not ready to pay up for the UN target of getting 15 million people on treatment by 2015. An estimated six billion dollars a year will be needed to fund the extra drugs.
France is leading the negotiations for the European Union, which insists it has taken a "respectable" position in the AIDS talks.
In a sign of the anger of many non-government groups, the AIDES and Act Up Paris groups accused France and Europe of "murderous duplicity" by signing up to a target of getting treatment to at least eight million people but refusing to promise finance.
Celebrities have also spoken out strongly in the AIDS campaign.
"Negligent non-action as a response to the HIV-AIDS epidemic, as it affects women and girls is just as bad, just as accountable as criminal action," said Scottish singer Annie Lennox told a symposium on women and AIDS at the UN headquarters.
American star Alicia Keys said world leaders had the means to save millions of lives in Africa. "The question is are we going to do it or not?"