Not so long ago, these lenses weren't given a second glance by photographers.
They were always fitted to Russian Zenit cameras, the heavy (and ugly) 35mm SLRs.
It would take a huge shift in technology with the advent of digital cameras and a desire for photographers to have different and atmospheric images that has led to the humble little Helios 58mm lens being the hero of swirly bokeh and dreamy looking photographs.

Prices have crept up over the last ten years.
You could pick one up in very good condition on ebay for around £20 back then but you can expect to pay anything up to £100 and beyond for more exotic variants that have been modified or have adapters supplied with them.

The Helios 44-2 is copy of the Carl Zeiss Biotar 58mm f2 lens which is a star in the world of photography and can sell for over £200.
Apart from their more realistic price, one of the things that make the Helios lenses (ad there are a few different versions out there) so attractive to photographers is the use of the M42 screw mount.
This simple design has created a whole new industry in adapters enabling us to fit many different vintage lenses to our new DSLR and mirrorless cameras.
In their simplest form, the adapters are machined discs that screw onto the lens and mount onto the camera, be it Canon, Nikon, Sony or pretty much any big brand manufacturer you care to pick.
There are adapters that have a built-in microchip. These chips work out when you achieve focus on a subject and activate the focus confirmation "beep" within the camera.
Most (if not all) adapters that I have bought have come from China and because of their incredible output in their factories, the adapters can be made and sold for very little money.

helios 44-2 58mm f2 m42 lens