You have three choices to make. How much do you want to spend? Do you want stainless steel or chrome vanadium steel? And what type of handle material appeals to you?
CV steel can rust and will tend to develop a patina (grayish color) over time. This just means you need to do a little care and maintenance along the way. Some people prefer the CV steel specifically because of the patina appearance, which gives it that well-used look over time. Case Tru-sharp stainless steel is pretty much maintenance free. Depending on your sharpening skills, CV is a bit easier to get a sharp edge on. The SS tends to develop more of a burr when sharpening that takes some work to remove. But the difference is pretty slim. Either will take a good edge.
Not all handle materials are available in both steels. So if you decide you like Chestnut Jigged bone then you are stuck with CV steel. If you like a Pocket Worn Old Red bone then you're stuck with SS. Yellow Delrin and Amber Jigged Bone are available in both steels.
If you're looking to save money, then the yellow Delrin and jigged brown or jigged blue synthetics are the least expensive and can be had for under $40, but in general the standard offerings would be under $50 unless you get into some of the limited editions or stag handles.
Me personally, I'd go for either the yellow Delrin or Chestnut Jigged Bone in CV, or the yellow Delrin or Pocket Worn Old Red Bone in SS, but that's just due to my personal tastes.