Having this morning received both an I2S DAC (PiFI DAC+, £14.50), and a USB DAC (generic, based on BB PCM2704, with h/phone, coax & optical SPIF o/ps, £5.50), I can confirm that Volumio on an RPi will drive this USB DAC. Since it has no volume control on the DAC, I set the 'Mixer Type' to 'None', rebooted Volumio, and it played to the selected USB DAC. Volumio drives the I2S PiFI DAC+ perfectly well, too, with hardware volume control on the BB PCM5122 DAC...
So that's about £30 for the RPi 3+, £5.50 for the USB DAC, and a 5V uUSB PSU, and you have a wireless music player you can control from any device on your home network that runs a web browser.
My RPi Volumio accesses my music library on my NAS. You'd have to decide how you wanted to access your music that's currently on your PC. Routers often have a USB socket that they can use to both create a file server and a media server from a connected USB HDD. Your PC and RPi Volumio could both then access this "poor man's NAS".