Several years ago, when I was first dipping my toes into the hobby, I did quite a bit of research on exactly this question. You'll find as many strong opinions on this subject as you care to read, which in the end can be overwhelming. I looked at most of the suggestions made here and in the end went for with a used Yamaha Natural Sound 800 series integrated, paired with a pair of used KEF LS50s and a Klpsch sub. Outlay for the entire system was right at $1500, and for the money, I've not heard anything better.
Of course I'm now about $35k deeper into this "hobby", with used Wilsons, Pass Labs, Acoustic Research and REL gear...so be warned, lol.
All very solid recommendations given here, and whatever you choose, I'm sure you'll be happy with it...for a while. 😆