Hi Guys - newbie here.
I bought some guillotine blades off ebay for just over 30 euros.
REPLACEMENT SHEET METAL GUILLOTINE BLADES | eBay
If they are no longer available you can use the CAD files to make your own.
I needed the rest of the guillotine for them to be of any use. Therefore I drew them up in 3D CAD and had the bits laser cut.
You are welcome to my CAD file.
For more info see my site
Hope it helps