For income tax purposes inheritance is not taxable income neither in the US nor in Arizona regardless the amount - as a recipient of inheritance you do not need to claim it as income. There is no any amount limit. Please see for reference IRS publication 525 page 30 - http://www.irs.gov/pub/irs-pdf/p525.pdf
In case some of inherited funds are in tax deferred account - 401k, IRA etc - that funds upon distribution will be taxable income for beneficiary.
For estate tax purposes - federal estate taxes might apply to estates with value above $2,000,000 (for 2008) - this tax is paid by the estate - not by heirs. There is no inheritance tax in the US. As the total estate value is $100,000 - there is nothing for you to worry.
Some states of the United States have estate or inheritance tax at the state level - so-called "death duty" - such taxes apply based on where the decedent lived or the inherited property is located. Neither Arizona nor Iowa have such taxed