they're readily available at flea markets, swap meets, antique stores, primitive meets, rendezvous
check the cutting edge and make sure it has no dings
other than that.....
have several myself, in different sizes and blade shapes. really like the little 4" ones for fine work. i always buy em if they are $12 or less and its fairly common to find em for $8 or less. much prefer the quality of steel of the old ones than the new ones, unless ya spend the big $. tho i did pick up a new mora(made in sweden-$22) from our local old school hardware store. nice