Americans will pay an average premium of $328 monthly for a mid-tier health insurance plan when the Obamacare health exchanges open for enrollment next week, and most will qualify for government subsidies to lower that price, the Obama administration said on Wednesday.

The figure, based on data for approved insurance plans in 48 states, represents the broadest national estimate for how much Americans will pay for health coverage under President Barack Obama’s healthcare reform law next year. The prices of the new plans are at the heart of a political debate over whether they will be affordable enough to attract millions of uninsured Americans.

Prices were lower in states with more competition among insurers and higher in states with fewer players, the U.S. Department of Health and Human Services (HHS) said in its report. Americans will be able to sign up for the new plans via online state exchanges beginning on October 1.

“For millions of Americans these new options will finally make health insurance work within their budgets,” HHS Secretary Kathleen Sebelius said during a briefing with reporters.