The equivalent of about 4 billion dollars in modern day money for both of them. That, plus waiting for some very opportune launch times so that we can gravity boost off of everything.
The closest in speed so far would be 'New Horizons'. But even then NH is going at 14.5KM/sec compared with Voyagers 18KM/sec. There are no probes currently that would catch up to Voyager.
And even more inconceivable is how slow it still is in terms of human spaceflight outside of the Solar System.
Travelling from New York to LA quicker than playing the song "From New York To LA"
The tyranny of the rocket equation is the fact that to carry more fuel to orbit, you need more fuel to get it into orbit, which itself needs more fuel. That's why gravity assists are so essential for escaping the solar system on a budget.
The planetary alignment that enabled the Voyager launch windows only occurs once every 175 years.
We should definitely be sending out more probes, but we can't just do it whenever we want, at least not without a lot more expense.
More conservative trajectories giving fewer flybyes but relying on more probes would be possible, and are in fact what we've accomplished with the Gallileo & Juno (Jupiter), Cassini-Huygens (Saturn), and New Horizons (Pluto) spacecraft. There are NASA (U.S.) and Chinese proposals for a return visit to Uranus and Neptune, though those remain in planning stages.
<https://www.space.com/nasa-uranus-orbiter-and-probe-mission-...>
The orbiter missions had a much longer time-on-station. For Gallileo, roughly 7 years 9 months, Cassini-Huygens 13 years, and Juno 7 years to date, with another 5 or more possible.
The Ulysses solar probe also flew past Jupiter, using the planet for an orbital assist to both slow it down to approach the Sun more closely and incline its orbit above and below the planetary plane so that the Sun's poles could be observed directly.
The problem with that idea is, except for a few geeks, no one wants to spend that kind of money on space probes.