That doesn't seem that expensive, I know some people spend this much for a single cup of coffee.

It's all relative.

For a chunk of humanity $5 is their entire discretionary daily spend (and for some it is their entire daily spend).

You shouldn't take modafinil daily though as you can develop a tolerance. You should take it 3 consecutive days and then rest the other 4 days of the week. Also extreme focus kills creativity so the rest days allow for a productivity/creativity cycle.

Can you elaborate on this? What are the specific positives of cycling Modiafinil, instead irregular single use?

ModafinilCat is well regarded and stocks the gold-standard Modalert for $2 a pill.