Congrats to both of you.
The list seems extensive, but you can start with an offshore R8 collet set and a few end mills. I started by buying premium collets one at a time, but I think that was a mistake. In hindsight I should have ordered a full set, from 1/4" to 3/4" in 1/16ths.
Get some offshore carbide or HSS end mills, they are find to start with. When you get toexotic materials, then you might add a premium end mill or two.
A cheal addition that you will need soon is a
test indicator. For the accuracy you need to start, an offshore one can be had for under 20$.
@YYCHM got one for 10 bucks, I think. You need this to square your vise jaws... a cheap (like Busy Bee) edge finder is also essential (I think I paid 6 bucks for mine).
This will get you cutting chips for under 100 bucks, but you will easily spend more than the mill to fully tool it - rotary table or indexer, vises, hold down kits, - the list is very long.
I'm in for about 4500$ in mill tooling - not including cutters, and just over 2000$ in lathe tooling (not including cutters).