If you don’t want to handle mains voltages, there’s nothing that immediately springs to mind. If you were replicating my test rig, you’d be getting the components from the likes of RS Components or Farnell/CPC, and by the time you’ve added it all up, it wouldn’t be cheap.You won’t see any change out of £120 just for the Variac, isolating transformer and heat sink.
If you are looking for something simple to do at home, then you’ve got little choice but to use the mains supply. For the load, you’re looking for something like convector heaters, oil-filled radiators, electric kettles and the like that will guarantee a nice clean waveform; the difficulty you face is getting at the wiring to put a c.t. on - and ideally with multiple turns available so that you can multiply the current.
If you’re doing it as a “semi-permanent” test rig, I’d get a cheap multi-socket extension lead, chop the cable in the middle and put the ends into a junction box, and bring out a length of single-core wire that you can put the c.t. on, with enough length to have a good number of turns. Then you can plug whatever load or loads you have available to get the varying currents.
But again, you need to take a lot more care if you have mains voltages. The beauty of my rig is I don’t care if I touch anything - as long as I keep my fingers off the load resistor, which gets quite hot. The side I’m handling all the time is 6.5 V. The mains side is as shrouded as I can make it - but it’s still possible to touch live metal if you try hard.