So for DO schools you can send an individual leter packet to each school for $6. So for each school that is six bucks, so it is wise to get them all in early so they can be bundled.
For MD, ACMAS handles the letters for you and your writers can send a copy directly to them, but then you have to have them send one copy to Interfolio and one to ACMAS. I chose to have my letter writers just send their letters to interfolio and then forwarded them onto ACMAS. The one kicker for me was that the way the process was setup on interfolio and the ACMAS, you had to send each letter individually so that was six bucks a letter. Now there could be someone outthere tha knows a better way but that was how I did it. I probably spent $100 at interfolio this year. But as I say “If you ain’t spending wads of cash during application season, You ain’t doing it right!”