Free: Contests & Raffles.
I would describe it as a tag that allows you to hunt mulitple seasons using weapons pertaining to that season.
I hope you're prepared to hunt the late archery or late muzzleloader season... otherwise you just wasted $140 on your multi season tag. Of course, I've heard of guys who also "wasted" their money by killing a deer on September 1st with a bow.
Does the WDFW actually issue you 3 tags? I bought my usual muzzleloader tag, then bought the multiseason for the first time this year. I don't recall receiving 2 more tags.
Which means you are only able to hunt modern firearm now, as if you never had it.