I believe cheapest and safest best would be Norton 4k/8k
You can go for a coticule, same price as norton 4k/8k can give you an okay size stone but smaller than norton and might be a bit harder to learn. Really need to make sure you get a nice coti though
Jnat I believe you could get one for around norton price and it be okay price as well.
Japanese chef knife. Sharpening stone. Razor strop. Japanese Razor Is a good place to look. You could buy a stone that isn't insane finisher but really good for touching up razor.
What would probably be easiest for you is to buy Naniwa super stone 8k and 12k. 8k for touching up and 12k for finishing. Can get a 5k for another 60 I believe. Stones are big and reliable