I'm an unapologetic proxy maker. Sand off everything but the border (and hologram for rares, if you care) on the front of the card, print HQ images on Windows's wallet size, glue printer paper onto blanked card.
So far the only drawback is double sided proxies are noticeably thicker and heavier than other cards. Still, saves me from dropping $30 on a Jace VP or worrying about a real one getting damaged lost or stolen.