Can I buy powerball or mega millions for a person in another state?

PowerBall and Mega Millions isn't a single lottery that spans multiple States as each State has the authority to sell lottery tickets only in their State. These multi-state draws are actually a separate lottery in each State that share the same draw and have fund transfer agreements for the major prizes. A Texas Powerball ticket is actually to a different lottery than a California Powerball ticket even though they are for the same draw. You can buy whatever lottery tickets you want to for whomever you want to but any winning tickets must be claimed in the State of their purchase. The ticket that you purchased in NJ or NY could not be claimed in Arizona should it win.