Instead of asking - what knives/steels are you planning to sharpen. I am guessing you probably want gears capable of sharpen today & tomorrow high alloy steels, all for around $50.
$15 HF 4 sided diamond block
for all rough grind
$12 3M wet&dri SiC sandpaper 1000,1500,2000 grit (each grit pk has 5 sheets)
for most normal sharpening tasks. You can cut each sheet into 5 pieces of 8x2, double-side tape it to a something hard & flat preferably with extra length to serve as a handle. Use mouse-pad backing if you want to convex your edge.
$20 DMT 4" Diamond Whetstone Extra Extra-Fine
get your edge toward too-sharp too-smooth too-knut world.