I would guess that the most expensive part of such an endeavor wouldn't be the launch; it would be developing and building a spacecraft capable of capturing it and bringing it back.
Even the Space Shuttle wasn't necessarily a perfect fit for the job as-is. Hubble was serviced many times, but it was specifically designed for on-orbit capture and servicing by the Shuttle. Before they decommissioned the shuttle they actually had to install an extra piece of hardware to make it feasible to capture and de-orbit using future non-crewed spacecraft. And even then that's just to make sure it crashes in a safe place, not to bring it home intact.
There was also a mission to service a satellite that wasn't designed for the purpose, and they had a really hard time capturing it and very nearly had to give up after days' worth of failed attempts. It finally took simultaneous EVA by three astronauts to coordinate a successful capture (one to grab it by hand, two to get it onto a specialized adapter rig built just for that satellite so that the Canadarm could hold it), which is quite a thing considering that the Shuttle's only designed to allow two people on EVA at a time.
This craft is likely tumbling, which I presume would make it unacceptably dangerous for a crewed mission (and certainly rules out anyone just going out there and grabbing it with their hands), in addition to making successful capture that much more difficult.
Even the Space Shuttle wasn't necessarily a perfect fit for the job as-is. Hubble was serviced many times, but it was specifically designed for on-orbit capture and servicing by the Shuttle. Before they decommissioned the shuttle they actually had to install an extra piece of hardware to make it feasible to capture and de-orbit using future non-crewed spacecraft. And even then that's just to make sure it crashes in a safe place, not to bring it home intact.
There was also a mission to service a satellite that wasn't designed for the purpose, and they had a really hard time capturing it and very nearly had to give up after days' worth of failed attempts. It finally took simultaneous EVA by three astronauts to coordinate a successful capture (one to grab it by hand, two to get it onto a specialized adapter rig built just for that satellite so that the Canadarm could hold it), which is quite a thing considering that the Shuttle's only designed to allow two people on EVA at a time.
This craft is likely tumbling, which I presume would make it unacceptably dangerous for a crewed mission (and certainly rules out anyone just going out there and grabbing it with their hands), in addition to making successful capture that much more difficult.