How much do I need to spend to get a preamp that sounds better than no preamp?

"Any! active stage/s introduces noise hum and distortions, increase their gain and you increase those as well." 

Nonsense. I don’t care who said this. Active circuits have long been proven to be less noisy than a simple resistor for proper buffering and volume control applications. Why? they have both high input impedance to precisely preserve input signal and low output impedance in order to drive whatever follows.

“Well I got the pass preamp and to me it sounds a bit thin on the bottom compared to no preamp. The vocals aren’t as warm and there is not as much Bass. Crap”

As posted earlier - for adjusting the sound and for fine tuning - get a tube preamp. Very little benefit to an SS preamp except that all decent ones should be transparent to the point of being not too different from stock SS sound from an SS device.

For example, a tube preamp with 12AX7 tubes is going to be highly configurable by rolling tubes and those tubes are not hugely expensive and there is a wide selection.

Unless you get a quality tube preamp then there should be little difference from adding an SS preamp in the path. A quality tube preamp will not necessarily be transparent but good ones will give you a wonderful warm presentation. Keeping signal levels as high as possible without clipping can be extremely important to get the most out of a preamp.