<p>Establishing residency is not that difficult - it depends on the state, but in many states it simply requires living independently in the state for a year prior to application. Proof that the person was self-supporting, such as pay stubs and a tax return - and other indicia of residency, such as getting a driver's license, registering to vote, signing a lease, and utility bills mailed to the local address would all help establish the residency. </p>
<p>Qualifying for financial aid is a different matter -- no matter how truly independent, an undergraduate student will be treated as "dependent" and parental income included up to the year that the student turns 2. A grad student will be presumed to be independent, however... and a young student living on his or her own can also gain "independent" status by marrying. (Pretty dumb idea for most 18 year olds, but certainly a reasonable course of action for many 22 year olds).</p>