There are multiple non-profits selling carbon offsets, usually at very reasonable prices. But it's not a regulated industry and the science behind this kind of analysis is complicated. None of them are selling simple products like "yes, we absolutely sequestered this much CO2 on an energy budget of this many MWh", so whether or not their projects "work" depends on proving how long their forests will stand, etc... There's serious worry that these organizations do more harm than good by significantly overstating their net offsets.

Really the only verifiable solution to carbon output is going to be reductions in net production.