The big one is $150 & the small one $50 on Offer Up (used) so not too bad really. New, would be a different story.that's a fused drop box. loads of different ones about at different price points and ratings. most work the same but do your home work. check the specs. most of this stuff is easier / cheaper if you look past just hydro / growing equipment.
we just built most of that stuff for a fraction.
But it makes things easy for some who don't want to wire a bunch of outlets.
I ran a 50 Amp sub panel to my shed & everything out there has a breaker for each outlet. There were no walls in my shed so it made running the electric easy.
I'm just not too sure about the 100 Amp Service being enough for all the power he plans to use. My dad has 100 Amp & the Electric Co. wants $5000 to upgrade the main box to 200 Amp. I pay $5000 for a box I'm taking it with me when I go.... lol.