the cassette alone is indeed worthless.
the entire package (4 discs and this cassette gimmick) is a 2012 release, less than $40 for all of it, so $3 is the top limit for the cassette alone. you can buy entire SP cassette collections for less than what you are offering for this one.
http://www.cdjapan.co.jp/product/TOCP-71238
"Non Japan-made disc. Deluxe edition of "Pieces Iscariot" release from The Smashing Pumpkins. 14 original tracks feature the latest digital remastering. This edition includes a bonus CD with 17 unreleased tracks, a DVD with 24 live tracks, a cassette with 6 demo tracks. Also comes with liner notes by Billy Corgan and a booklet with unreleased photos."