Nobody has to cover the difference after all estate assets have been used to pay creditors. The creditors take the loss and the heirs inherit nothing. But let's make sure you understand. You said "not enough money." Did you mean that all of the assets of the estate would be converted to cash and then there would not be enough money? Or did you mean that there are other assets besides money? All of the assets of the estate, not just the money, will be used to pay creditors to the extent possible. Nobody can inherit any part of the estate as long as there are creditors unpaid. So if you are asking whether the people who are named heirs of the house, car, stock, horse, diamonds, family business, etc. will have to contribute to the creditors, the answer is that their inheritences will be reduced or eliminated as necessary to pay the creditors. But after the estate assets have been used to pay the creditors in part and there is nothing left in the estate, nobody has to contribute anything more.
This answer must not be relied on as legal advice for the reasons posted
here: http://mcgyverdisclaimer.blogspot.com . And I am not your attorney.
No personal representative/administrator is personally responsible for paying the bills which I assume is your primary concern. If there is no surviving spouse who can be held accountable for certain bills, then pursuant to statute the remaining funds are used to pay bills in a certain order. Aministration costs of probate, fees for probate and PR fees receive priority if funds are limited. It is all set forth in Wis. Stat. 859.25. As to other types of bills/claims, secured creditors are entitled to the secured property and or the full amount of their secured interest .
Stephanie and David provided the basics, the estate assets are liquidated and used to pay the bills. The personal representative does not have to cover any unpaid bills.
You can review the details of Wisconsin Statute Section 859.25, which governs Priority of Payment of Claims and Allowances, here: http://www.legis.state.wi.us/statutes/Stat0859.pdf
Depending on the specifics, an Informal Administration of the estate may suit your circmstances. Wis. Stats. 865 governs Informal Administration and can be reviewed here: http://www.legis.state.wi.us/statutes/Stat0865.pdf