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

There are a few sources that require active preamp, without while your system sounds lifeless. I had Logitech Bluetooth receiver which was one such example. Similarly connecting the headphones out from a mp3 player to a passive also sounds lifeless. I use a TVC. 

@kosst_amojan,I used Signal Cable's Silver Resolution as well as Clear Day cables for the BT unit, not the ones that came with the unit.
@georgehifi ,I have nothing against passives. In fact I have been using TVC for the past 9 years. You bring up Nelson Pass's statement that we have enough gain in today's sources to drive power amplifier. Yet he keeps coming with new preamps. There must be some reason for that - besides the "making money factor". I feel that audio is a personal choice and "how" a system sounds is a personal preference. With my upgraded loudspeakers, I am tempted to try a active in my system. Why? Because my new loudspeakers have better resolution. And I am hearing stuff that my old speakers never showed before. I would like to see how an active preamp works in my system.