I like the lee scale for measuring powder, I only use my electronic scale to sort bullets and brass.
Cleaning is pretty straightforward, a few drops of dish soap and some warm water is all I use. Get a bottle brush or if you have an sks, the cleaning brush that comes with it works pretty good. The main thing you need when starting out with the lee challenger kit IMO is a vernier caliper and lots if books. You will also need a comparator and a way to figure out your throat length if you plan on loading longer than max coal. After you spend a bit of time researching the type or bullets and powder you want to use, stick with it for a good while so you can see how every little change you make affects your performance and accuracy. Don't mix brass types and measure case capacity. There's waaaay more to it than I mentioned here... Research and quality info is key!