I have an Audioengine D1 DAC, list is ~$170, playing FLAC lossless flies through JRiver, on a standard PC, sounds good for a relatively modest investment. I use a USB connection, but the D1 also has an optical input if you prefer.
Foobar is free and can also do bit-perfect playback. Jriver has an indication in the interface for when it is running bit perfect, which is nice. Foobar is much lighter weight - smaller download, faster to start up - which is nice.
Unfortunately, jriver doesn't play well with my DAC's remote. I may pursue it with them, or just keep using foobar.
I'm using an Arcam irDAC-ii which has usb, optical and coax in, and has line as well as variable outputs and a headphone amp built in. It can also do bluetooth, and if you have aptX capable sources will do aptX reception.
It sounds quite good. List is around 800, but you can find them new at 550 online, and lower if you're willing to look at used gear.
It does not sound as good as the Ayre Codex, which I can't afford at nearly $2000.
As an example of the Arcam 'sounds good,' last night I stumbled across
https://www.npr.org/sections/therecord/2015/06/02/411473508/how-well-can-you-hear-audio-quality and using the headphones (it was late) picked the uncompressed recordings 5 of 6 times. The sixth sample, the Katy Perry, I picked the 320kbps track. I found that I was guessing on two of the tracks in each presentation, and picked the track I came back to more often.
What that means to me is that the Arcam is good enough, paired with decent (Senn 598) headphones that I didn't spend much time listening to low bitrate material and generally gravitated to listening to the least compressed recordings when using it. If I'd truly been guessing, I should have had an equal chance of landing on the 320kbps track as the most interesting sample.
When I listened to the Ayre and the Arcam side by side, the Ayre was able to show me things about the recordings that I hadn't known before. The Arcam reproduces music faithfully and well, but the Ayre gave me insights into what the artists were doing that I was very impressed by.