I was reading this article and thought it was reasonably cheap, probably because I mistook LEO for GEO.
What is the going rate to get something into GeoStationary Orbit and Geosynchronous Equatorial Orbit?
Do these prices exist?
We have a similar question in What is the current cost-per-pound to send something into LEO? While launching to a Low Earth Orbit (LEO) is of course expected to be a lot cheaper per kilogram than lifting same mass to a Geosynchronous Orbit (GSO) or a Geostationary Orbit (GEO), be it because of an individual GSO/GEO capable launcher's payload capacity to LEO being much larger than that to GSO/GEO due to smaller Delta-V requirements to achieve it and the cost per kilogram spreading over a theoretically much larger total payload mass, or due to LEO launchers being simpler and more cost effective, when altogether different launchers are used, that mentioned question might still prove relevant in the future, when the launch prices are updated to include new, yet to be developped launch systems. So think of it as future-proofing, and whichever thread updates faster will probably have more up to date information available.
To answer your question however, some launch prices are available to the general public as some launch systems are commercial in nature, while others might be partially commercial or the costs of their space services completely funded out of budgets of various countries. So this information will be a subject to availability for various reasons. But there are some launch services that disclose the cost to GSO/GEO per launching system and the Wikipedia page on Comparison of orbital launch systems currently lists a single price per kilogram:
Comparing it with prices per kilogram to LEO given in the @PearsonArtPhoto's answer, this seems to suggest a roughly double and higher the price to Geostationary Transfer Orbit (GTO) than to LEO. GTO is of course merely a transfer orbit on the way to GSO/GEO, so a large part of this mass will be your payload's thrusters, which is a dead weight once your destination orbit is achieved. Comparing GTO to GEO capabilities of most of the still operational orbital launchers comes down to a factor of roughly 2:1. So in short, your cost per kg to GEO will be roughly double that of the cost per kg to GTO, but as it depends on many variables and data we don't have, I'll use GTO to calculate the estimated price to GEO.
Direct comparison with LEO launchers is a bit tricky though, as there are of course many more launchers available to LEO, they might be a lot simpler by design with fewer and/or more reliable stages, and smaller SRBs (Solid Rocket Boosters) strapped to their first stages. But let's try to infer from that Wikipedia page what other GSO/GEO capable launchers' prices might be, regardless. Adding
20% 10% (using Atlas 401 to 541 calculated difference of 6%, but let's round that up for good measure since it's a guesswork) to the cost to LEO approximating more powerful and expensive SRBs or additional upper stages needed on same launch systems to reach GSO/GEO (yes, this is blatant oversimplification, but should be close enough), we'd get:
And so on and you get your average price per kg to GTO at $\approx$ \$US 25,000. I'll repeat again though, these are guesstimates for GTO, not GEO (you should roughly double the price to GEO per kilogram, depending on your configuration, as described before), and shouldn't be used for anything else than to compare price per kg to LEO to a ballpark price of GEO at $\approx$ \$US 50,000 per kg.