I often get asked how to print in metallic gold foil at home.  Although you can't print directly in metallic gold from any home inkjet or laser printer, there are a couple of ways you can add gold foil to your DIY wedding invitations right at home.  Source.
Being the thrifty lady that I am, this first method is the least expensive one out there.  to get started you will need:
1. Inexpensive Laminator.  I found this one for under $20 on amazon
2. Deco Foil.  Available in many colors, also on amazon. $6-7 for 5 6x12 sheets
3. Laser printer.  You can print on your own laser printer at home like I did, or use a place like staples.  Inkjet prints will not work.