I don't know what to tell you. You have to have a knife that will generate the ticket sales you need to raise the funds you need but the knife has to show value to the person buying the ticket without pricing your buyers out of the market.
Case in point: the cancer research knives are absolutely drop dead gorgeous but at $100 a ticket are out of my league. If you have a knife that I perceive to be worth, say $200, and tickets are say $1 each or maybe even $5 for 6 or $10 for 12 I'm probably in for at least $10. $20 if I find your cause particularly appealing. However the same $200 knife at $5 a pop, you may only get $5.
Sorry, not much help I guess... Best of luck with your decision and the fundraising though.