Where to buy or how to cut blank hexes for own game prototype?
Yes, you can buy blank hex pieces. Print&amp;Play Productions offers cardboard hex tiles in several different sizes through Boards &amp; Bits.

Chipboard Shapes - Hex 1.19" [35 pcs] $2.00
Chipboard Shapes - Hex 1.5"  [20 pcs] $2.00
Chipboard Shapes - Hex 2.2"  [11 pcs] $2.00
Chipboard Shapes - Hex 2.6"  [22 pcs] $3.00
Chipboard Shapes - Hex 3.9"  [8 pcs]  $3.00


You could also get wooden hexes from WoodNShop for $0.15-$0.42 each, or at a discount by the 100s. I am unsure if these would fit your purposes for tile laying, as I have heard complaints that the tile dimensions are not uniform enough for such a purpose.

 C/O HEXAGON 1/8 X 1 $0.15
 C/O HEXAGON 1/8 X 2 $0.20
 C/O HEXAGON 1/8 X 1 $0.32
 C/O HEXAGON 1/8 X 1 $0.42
 C/O HEXAGON 1/4 X 2 $0.20


There is also plastic tiles, if you are so inclined. With a little bit of work to remove the mesh backing, you could use actual hexagonal tiles from your local hardware store.

I don't know of any board game manufacturer that creates hex tiles with custom graphics. Board game maufacturers are capable of creating protype board games, but my guess is the cost is prohibitive.

If you want to cut your own uniform hex tiles, you are going to need a die cutter ($600), and a custom die.

You probably don't even need hex tiles for testing purposes. If the hex tiles need not be rotated, then square tiles can be offset every other row for the same effect as a hex tile. If orientation is important, wooden tiles/disks can be substituted for hex tiles.