The parts are really no problem, if you use Digikey. Just go to their web site and put in all those part numbers. They do charge a few dollars for shipping but nothing unreasonable. No minimum order. I have ordered a single part and they just ship it out the same day. They do offer quantity discounts, so if you wanted to build 10 of these some parts would be cheaper.
They also have a very intuitive search engine. Like put in “resistor”, and pick “thru hole parts” and they show you 20 billion resistors. Then you pick the resistance you want and the wattage and do select “active” and “in stock” to see what they actually have ready to ship. You can sort by any field (like price). Easy as pie.