USB cable

I have a mint used Acoustic BBQ "Double Smoked" USB Cable
listed on the other main audio website for under your budget.
Detailed and very natural sounding.  I don't know of any cable in its
price range that could get near its sound quality.

Oyaide Continental 5S or Intona basic cable. Keep it short, though!

Since your DAC has asynchronous USB the only issue is ambient electrical noise and computer noise injected into DAC - data will always be the same (timing is not involved).  I would try a cable with good shielding and no power wires (+5V, GND), since you don't need them.  Try before you buy, since cheap cable might sound the same as very expensive one (it is only the data).

Solid core cables are best for USB.  All Audioquest cables ae solid core, for ex.  Silver helps too.  A Hong Kong ebay advertiser of solid core silver USB cables made one up for me that is a great performer.  

I had been experimenting with USB cables and was shocked at what a difference they can make, especially if you have quality components at both ends.

Contrary to what @kijanki writes, even if your DAC or USB board is self powered you MUST have the ground connection (pins 4) connected or it will not work. And ONLY the data?

@melm  I thought it should work, since it is differential signaling (receiver detects the difference between +data and -data lines.  Receiver ignores any common mode (including GND reference).  Many people lifted GND (cut GND wire) and reported improvement in sound, but it might not work if system uses Single-Ended signal for handshaking.  Easy to try with cheap plain cable.  I will read more.

USB cables made no difference in some systems and huge difference in others.  It can be attributed to the type of the DAC.  When DAC is synchronous cable can affect timing, but with asynchronous DAC timing is not involved.  Better shielding plays role, but very expensive cable doesn't have to be better - try before you buy.

You almost always will need the ground as the common mode range of the differential transceivers is rather small.

Audio2design - It makes sense.  Thank you.

There are people who lift the ground after handshaking takes place.  Others install a small resistor in the ground line.

The best USB I've heard close to this price is the Laboga Emerald.  It's not the easiest to source, and judging by the absence of mentions on this forum, probably doubly so in the States.

Of all the USB cables I trialled it's the warmest, most analog and most musical I heard.  I ended up, however, with the FTA Sinope as it's similar in character but just better.  And 3 times the price.

The Emerald deserves more exposure as it really is excellent.

I’ve just bought the top-of-the-line Wireworld Starlight 8 USB. I will see if all the hype about this cable is true in about 2 weeks time. I’m currently testing the WW silver electra 7 power cord and will install the platinum Starlight 8 USB after I’m done with the evaluation in about 2 weeks time.

In my experience keeping the cable as short as possible while separating the 5v DC line is the starting point. After that it’s down to single core and treating the connectors with Acoustic Revive or Mad Scientist contact enhancer. Depending on the Dac’s USB port inserting an Intona Isolator can have aubstantial benefits.