[SVD]

As to buying gravers I think your best bet is to go with one of the two companies that make the gear. Steve has some nice choices and his template based system lets you make your own flats or knife gravers.

Some ways to save money include using 3/16" carbide drill rod (heard about but haven't tried) and making several gravers out of each blank which I have done.

Get some 3/32" square brass tube and some 1/8" square. How long a bit of actual graver you need depends on the type of point but mostly you only need about 1/2". Use a short bit of the 1/8" tubing to join the graver bit to a piece of the 3/32" to get the overall length you want. Some folks silver solder (stand the piece on end in water, graver bit down to preserve the temper). I just use a punch to dent the 1/8" square brass and use some Gorilla Glue. There's not a lot of stress trying to take it apart. In use you're pressing it together so it just needs to not fall out when not in use.

Note: Make sure you can get the 'blank' in the sharpening fixture. The back end of the 1/8" can't be too far from the point or it won't work.

Edited to add: This is just how I implement John B's clever little gravers idea.