Phono Stage, How much do I need to spend, New or used.

I have a Phono Box RS ($1000). It is excellent and often looked over.
Get the outboard power supply for it ($700)... don't use the wallwart. It is quiet.

In that $1K price range, I would also suggest the Hagerman Labs Trumpet MC (can be used for MM carts as well w/adjustable gain). Tubes, dead quiet, and $900 (used even less). It’s a winner on value alone, let alone sq.

Speaking new prices, I think phono stage should be at least twice as expensive as cartridge. This is easy question to answer.

I started with an iphono and then moved to an EAR 834p, both used and under $1k. Good results with both. When I stepped up to the Manley Chinook SE, it was a bigger leap than going to the EAR. My vinyl outdoes my digital now, using a Hana SL and a VPI Prime. My digital is an excellent Lumin D2 with upgraded power supply. It comes quite close on hi Rez files. 

 denon pra 2000, Sony ES 77

also great option

Atoll and goldnote is also very competitivly priced and good