You'd think that it should be "a lot less" for someone paying cash, but this is almost never the case (in the U.S., anyway). Insurers can threaten to remove a hospital from their network if the prices get too high. The hospital doesn't want to risk losing the large stream of sick/injured patients from the insurer, and usually couldn't care less about one person deciding to have surgery else for reasons of cost (edit: see last paragraph).
Individuals paying cash (and individuals without insurance) are generally stuck with the "sticker" price for care (higher than what private insurers pay, and significantly higher than what medicare pays (medicare basically gets to "declare" what they're willing to pay for a given procedure and hospitals generally have to go along with it or they'll lose some/all federal funding)).
It's usually very difficult to renegotiate the sticker price without an insurance provider or the government working on your behalf. If it's a time sensitive or life threatening procedure, you'll often have other more pressing action items than haggling over the price. It's even harder to negotiate after the fact, since hospitals make you sign away whatever bargaining rights you may have had before they'll agree to treat you.
[edit]
Finally, hospitals generate the bulk of their revenue from insured patients. They can and do quote higher prices to uninsured patients, but the fact remains that this is a fairly risky patient pool for the hospital, since many of these patients will sign whatever they need to sign in order to get treatment, despite being completely unable to pay the (relatively huge) prices quoted.
Hospitals have incentives to keep this pool as small as possible, and occasionally resort to extreme measures (legal or otherwise) to get rid of these patients [1]. Though the hospitals often aren't able to collect the full price from many of these patients, you would be naive to believe that they won't send collections agencies after you and utterly ruin your credit rating if you find yourself unable to pay.
I've never had major surgery so perhaps it's different for that, but I've found (through periods of no or crappy insurance) that doctors visits are significantly cheaper when you say you're paying in cash.
Individuals paying cash (and individuals without insurance) are generally stuck with the "sticker" price for care (higher than what private insurers pay, and significantly higher than what medicare pays (medicare basically gets to "declare" what they're willing to pay for a given procedure and hospitals generally have to go along with it or they'll lose some/all federal funding)).
It's usually very difficult to renegotiate the sticker price without an insurance provider or the government working on your behalf. If it's a time sensitive or life threatening procedure, you'll often have other more pressing action items than haggling over the price. It's even harder to negotiate after the fact, since hospitals make you sign away whatever bargaining rights you may have had before they'll agree to treat you.
[edit]
Finally, hospitals generate the bulk of their revenue from insured patients. They can and do quote higher prices to uninsured patients, but the fact remains that this is a fairly risky patient pool for the hospital, since many of these patients will sign whatever they need to sign in order to get treatment, despite being completely unable to pay the (relatively huge) prices quoted.
Hospitals have incentives to keep this pool as small as possible, and occasionally resort to extreme measures (legal or otherwise) to get rid of these patients [1]. Though the hospitals often aren't able to collect the full price from many of these patients, you would be naive to believe that they won't send collections agencies after you and utterly ruin your credit rating if you find yourself unable to pay.
[1] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1646410/