I spent a total of $650ish on a chiller that’s made from a fuel tank I insulated the daylights out of and mashed up with a 25.5k btu window ac unit- gets down to -30c can run it all day, temp never gets above -8c even under heavy load for hours.
Check thread pretty much all the data is there, if I ever need to cool a different system than my rotovap I just drop another submersible pump in and run lines.