Where are you located?
State side Straight Razor design.
He will need a
Razor (I know obvious )
Strop
Brush
Soap or cream
And any post shave products he prefers.
$100 is a tight budget for the entire set up if you are going to get new.
Larry over at whipped dog is very helpful as well and could get you into a used piece staying at your budget.
You can pick up the phone and call any of the vendors you see advertised on SRP and you will get advice, help, and guidance.
I would also let him know we are here, this site is an invaluable resource for wet-shaving.

If you are overseas there are also some great options that others can fill you in on.

Regards
Pat