Other good options would the the Case easy to open/close zytel lightweight, also no one has mentiond the Camillus Sierras, excellent knives simliar in design to spyderco, but cheaper (can be found for $25 or less on-line) although not as good bladesteel 440A vs. VG-10, but for the money they would be hard to beat. Also the Heckler and Koch lockbacks made by Boker look very impressive, but more expensive.
For my money I'd stick with Spyderco, either a Calypso, Delica, or Native, or Vesuvius, could not go wrong with any one of them and the most expensive is almost 20 dollars under your price cap.
If I were to rule out Spyerders I'd get either a Benchmade Griptillian or a Boker, either a Walter Brend or HK P2000. All these are close to your price cap.
If I wanted most knives for the money but still wanted good stuff I'd get Byrds or Camillus Sierras, or an Oddessy by Buck.
Nothing personal but don't buy any Schrade "tactical" folder, and I personally DO NOT like Gerber knives (I know they're good quality but I don't like their designs) and in all honesty I would not buy a tac folder that wasn't a Spyderco, Benchmade, Boker, or Camillus, they make some AWESOME stuff, CUDA, but all of it is well above 80 dollars.
Let us know what you end up with
