Budget phono stage under $100, cheap but refined, does it exist?

Mwatsme

I can really recommend a Teac TN-300 as a good budget TT cw built in phono as I bought one a few years back and still have it in my daughters system and she plays a lot of music on it!
It comes cw a cartridge AT95E and built in phono and usb if you ever wanted to digitize your record collection.

I upgraded with an Ortofon 2m red as it was laying around but with the AT is was no slouch.

You can pick them up on eBay for about $240 or so.

Just my thoughts.

The chassis costs more than $100 to make!

I would recommend the Schiit Mani as well. I had the Emotiva XPS-1 before getting the Mani and the Mani definitely has a wider soundstage, more separation and better dynamics overall. The Mani is a great preamp for the money.

some people have reported having issues with the Mani picking up RF, which is an issue I haven't run into. 

Upgrading the NAD PP2 with a good, regulated power supply and discrete op-amp will put you in a good place. The PP2 (cost about $100 used on fleabay) can be run stock until you raise the funds for the upgrades. You can probably do similar upgrades to Pro-Ject and Cambridge units, but ymmv. 

 a Musical Fidelity VLPS II with s seperate power supply is great bang for the buck