They are not expensive anymore. The 1st generation device that I use (ATN Viper) can be had for $250-300. Others have talked about a toy called "Eyeclops" which may be serviceable (except much less convenient) for about $50.

But getting back to snip tests... Tkamiya has asked about how to get the worst possible grain from Tri-X...

This is a perfect example where snip tests will come in useful.

There are lots of ideas thrown out, develop in Dektol, overexpose, intensify, reduce. Four or five experiments could be done on one roll of film.