They are available from Toyota, but the only difference is the OEM stamp, and the cost between $350 to $400.
When you replace the windshiled also purchase the trim strip that runs along the top of the windshield. The old one won't fit the new windshield very well.
One major cause of windshield cracking is opening the hood too far. The sides of the hood dig into the windshield when opened much further than the prop.