The C is for Crank
Working Families Tax Credit Benefits Families. Single or Childless, Not So Much.

The most obvious objection to Gov. Chris Gregoire's proposal to pass a temporary half-cent state sales tax is that sales tax is, by nature, regressive---that is, low-income people spend a far greater percentage of their income on sales tax than higher-income folks.
Nonetheless, some lefty organizations---notably the Washington State Budget and Policy Center, a progressive think tank---are supporting the tax, in large part because it include a so-called "Working Families Tax Credit," essentially a rebate for low-income families.
Emphasis on families. The more kids you have, the more you benefit. For example, if you're married and have three kids, you can get a rebate of up to $567, depending on your income. In contrast, if you have no kids---even if you're married and filing together---your maximum rebate drops all the way to $50. Essentially, the rebate is a reward for having children that will do little or nothing to help working couples and single people who are low-income but don't happen to have kids.

Keeping in mind that $13,000 is approximately one-third of the median income for Washington State, here are some specific examples of how the rebate would apply:
A married couple with three kids can make up to $48,000 before their rebate drops to the minimum of $50. A similar family---married, three children---making $16,000 would receive the maximum rebate of $567.
In contrast, a married family with one child can only make up to a total of $40,500 to qualify for the minimum $50 rebate. A similar couple with one child making $16,500 would qualify for a maximum rebate of $16,500.
If you're a single parent, a parent in a domestic partnership, or a parent who's in a committed relationship but unmarried, the income cutoffs for receiving any rebate becomes significantly lower. If you're a single or otherwise unmarried parent with three kids, for example, the most you can make to qualify for the minimum $50 rebate is $43,000. That drops to $40,000 if you have two kids, and $35,000 if you only have one.
But the really dramatic drop is for people who don't have children. If you're married, the income cutoff for the minimum $50 rebate, for two people, is $18,000 a year. And for those without children, a $50 rebate is also the maximum---even if you only make $100 a year, $50 is all you get. If you're single, $50 is all you can qualify for, too---except in your case, you can only make up to $13,000 to qualify for any rebate. A single person making $13,500---again, about a third of the Washington State median income---would get no sales tax relief from the state.

Put another way: A married couple with three kids making $13,000 gets a rebate more than ten times larger than a single person or couple without kids who makes the exact same amount.
Obviously, kids cost money; people with kids should, in fairness, get a larger rebate. But I simply can't accept the premise that the mere fact of having children should qualify parents for a rebate ten times as large as single people---or why the income cutoff for single non-parents is a quarter of the cutoff for married people who've had three kids. If this is how advocates for the tax credit have made the sales-tax proposal "progressive," count this single, childless taxpayer out.