Optimized for US Letter (8.5" × 11") cardstock: eight cards per sheet in two columns. Each card is still 3.5" × 2" (standard size).
Print at 100% scale (actual size, not “fit to page”). Turn off headers and footers. After printing, cut along the small gaps between cards (about ⅛" spacing).
HP Envy 4500 (and similar): In the browser print preview, set scaling to 100% (not “Fit to page”). In the HP print dialog / preferences, pick paper type Plain or Cardstock, and use Best or Normal quality so the blue/red/gold panel prints clearly. If a sliver of the grid still clips, try Minimize margins in the browser only if it offers that — the page already leaves a half-inch safe area.
Download PDF matches the preview above (same layout as print) — best if "Save as PDF" doesn't show up. Print is for your HP or another physical printer.
For the print dialog: open the destination dropdown and pick Save as PDF or Microsoft Print to PDF. Use 100% scale.