High-Res Car Sign Design

I’m preparing a vinyl car sign that must print cleanly at 18 inches tall by 24 inches wide, even if the shop scales it up. The artwork therefore has to be supplied at a true 600 DPI (≈10,800 × 14,400 px) with absolutely no pixelation or blur... (Budget: $10 - $30 USD, Jobs: Adobe Acrobat, Adobe Illustrator, Adobe InDesign, Graphic Design, Illustrator, PDF, Photoshop, Print Design)