There are many systems capable of performing close to LN2 temps for long-term use.. such as Phase cooling.. Cascade Phase to be exact. Other than that, your looking at roughly 8-15k$ for a system to pump and monitor temps, with auto-LN dispersal. There are no such systems capable for LHe as its much too cold and explosive.
There are several Phase builders on the forum capable of constructing a custom phase unit.. starting around 1.2-1.5k$..[these are custom units though.. and price varies on your demands for the build and the builder] or some where near the area from the pricing I have seen. These systems can produce temps into the -140c range with good reliability. Going colder is not really possible for 24/7 as you will have issues with condensation and warping over extended periods of time.. which will ruin your hardware permanently.
**I recommend using google to look up the "Goliath" cooling thread on XS.. if YOU are serious about what you are talking about, that will be some-what of what is possible for 24/7 use with very -0 temps.