Yeah, those drop checkers are nice and will certainly impress any guests coming to your house and you can show them that and the Co2 setup, etc.
With a lot of practice, you can make your own. You can buy these glass rods that they use for scientific glass blowing and with a torch you can make them, blow the bubble reservoir, bend, etc..
I tried a few times to make a simple drop checker. Blowing the bubble reservoir is not too hard but bending to a "U" shape is what I have trouble with. I ended up making one out of a test tube that I bent to a U shape. It works.