The only limitations to crafting are time and money. If he can afford 100 then he can have 100. They are normally a bad investment however due to their cost. As for his cohort crafting them, there is no rule against it.
|
one of my party members has a lvl 13 wizard cohort, whom he wants to use to make constructs, given that he may have the money what are the limitations such as how many he can have at a time and if i should allow a cohort to be able to craft them.
The limits on construct crafting are money, time, and prereqs. If he's a cohort (2 levels below APL), the constructs will be bad, as they won't be of a CR over the cohort's level (almost always), and if they're destroyed that money is gone forever. Let him make as many constructs as he wants, they're pretty bad anyway.