What is a consistent estimator?

Because it is easily influenced by extreme values (i.e. it is not unbiased).

I believe you want to say, "as the sample size increases" I find this definition on Wikipedia that might help: In statistics, a consistent sequence of estimators is one which converges in...

Yes, a free income tax estimator can be as good as a paid income tax estimator. A tax estimator just allows you to have an estimate of your tax return.

Nope.

Mass is completely consistent. The amount of mass and matter on earth never changes, but is only recycled again and again. no but density is