1) I’d recommend grey for brush on primers.

2) For brushes, don’t go too expensive or too cheap. Somewhere in the middle is good- I’ll link a set of quality brushes for a good price here

3) As far as paint sets go, can’t go wrong with any Vallejo set, such as this, this, or this

I bought a near-identical set when I started a year ago, and after a few months settled in using Nos. 8, 4, 1, and 3/0 exclusively for every mini I paint. About 200 models in, and they’re still working fine.

My take on it is that this is a good compromise for a beginner who’s uncertain about the hobby. You don’t want to invest in something nice that might be ruined by a simple mistake; neither do you want to buy a truckload of something cheap that will just end up in a closet or landfill if you no longer find it useful.

Honestly the cheap packs of brushes are fine. If you take care of them they can even last a while.

https://www.amazon.com/dp/B075L8LCTG?psc=1&ref=ppx_yo2ov_dt_b_product_details

These are surprisingly not horrific. The only issue I have with them is that the tip tends to start curling after a while. It can be mitigated by turning the brush occasionally so that you're using it evenly all around. They hold their tip relatively well, don't split all too much, and are overall pretty good for the price.

And really you only need a single "expensive" brush that you save for the fine detail work. I got a Redgrass games brush and it's been alright. The tip is really nice and pointy but it has more issues with hairs splitting than any of the cheaper ones I have. It requires a bit more finicky work to get it into a proper shape, I've found. So just because something expensive doesn't mean it's automatically better than the cheap stuff.

I'd suggest saving up enough money to buy a single size 1 brush from Windsor or Artis Opus. 25 bucks for a brush is a lot but as long as you take care of it it'll last you a while.