Good for you!
Most hospitals, etc. work this way. Sometimes they don't charge interest. They are happy if people just pay.
Also, there may be some kind of tax deductions for medical bills that help a little. (Not as much as the guvmint not taking your money in the first place, but that's another story!)
I also want to remind people about medical savings accounts. Check them out! Some even allow you to pay for OTC drugs, etc.
the IRS pub on Health Savings Accounts---
http://www.irs.gov/pub/irs-pdf/p969.pdf
It's also worth noting that you should speak to a tax accountant if you incur a large medical expense like this. I believe medical expenses above a certain threshold are tax deductible, and if you pay interest charges on the original cost then the interest may be tax deductible, too.