So they all do essentially the same thing in principle, which is turning the bass/treble up and down with a filter. Imagine playing a note and then rolling your pickup tone up and down, it's essentially the same thing.

The differences between pedals are basically what filter is being used, what frequency range it has, build quality etc.

So yes, you can get a similar effect with a cheaper pedal but no they do not all sound the same.

Personally I think the Crybaby is fantastic and absolutely worth the money, but I bought mine when I was 14 (which was a loooong time ago now) because I wanted to be Jimi Hendrix, I didn't consider any alternatives because... I was 14 and 14 year olds are frivolous.

Don't spend your money just yet, I would say you need to go to a guitar shop (if you can) and try 3 or 4 wah pedals and see what you like, and if you can find something that sounds great for less money then go for it!

But equally, if you can afford the crybaby and that's what you want then it is an excellent choice.