Well, you need a programmer to upload a bootloader to a microcontroller. If you have a friend with a programmer already, you can borrow it to install a bootloader on your mcu. Then you won't need a programmer again, and saved yourself a few bucks.
Otherwise, if you don't mind the ~$36 cost, you can get a nice programmer from mouser.com/digikey.com. Its the more expensive one linked on the first page of the $50 Robot tutorial.