The swiss Army is a somewhat common knife, I bought the same knife used for about $25 on ebay about a year ago for day to day usage. Being unused and in original box will help but I think you have it pretty high, but I could be wrong. I find that the little Swiss Army Knives (or SAKs), called the Classic, with the blade, file and scissors go for $10 all day. I find them occasionally at a thrift for $1 apiece and get them every time I find one.
The real find for the SAKs are the ones with the aluminum scales, called I believe Alox. If you find those, those are prized. Pay premium for them, you'll make money.