Low Cost DACs


Currently I have my laptop connected directly via 1/8 jack from headphone outlet into 2 RCAs directly into my tube amp. Quality of sound is lacking to say the least!
I am considering adding an inexpensive DAC ( iFi AUDIO nano iDSD LE Portable DAC  or iFi Audio nano iOne DAC ) into the stream between the laptop & amp.My question is: will this influence the overall sound I'll hear out of my speakers? Will adding such a DAC help to increase the quality of sound produced by the system?
I'm not interested in spending a lot of money on a DAC as this is a source that I don't use as much as some others already in the system.
wcc10
Thanks yyz.The microRendu looks like something I would/should want! I checked out their website and this is a cool piece of audiophile equipment. I need to give this some thought. As I stated, I mostly use the OPPO and Vinyl at this point. But the upgrade bug has caught me once again. Just spent over $2k on a new camera so this may have to wait a couple of months!
Why not an endgame dac at low price, especially used : Starting Point Systems dac Nos TDA 1543 +internal battery.... Minimalistic design, organic sound, low noise level... It is my endgame paid 20 bucks on Ebay which can be bought used around 100 bucks... 
Cambridge DacMagic for 75 is a great little unit.  Personally, instead of using a laptop with pandora I have found that using my cell with Tidal gets much better quality sound and I can download as much as I want to my phone.  And you can take the phone and dac with you anywhere.
The only problem I have with Tidal is the $20.00 per month fee. Call me "cheap" but that seems a bit high. I did try it for free for a while and agree, it’s a better option than Pandora in terms of music quality..