Full hydro can be done cheap.
Used orbital $150
Ram $100
mod stock pump $0
Add reservoir/cooler $0-$50
Hoses $150
Full on complete Hydro kit $1400
Cheap Hydro assist $100-$150
Full on Hydro assist $900
I already have my rams so I have a PSC pump, res/filter, orbital coming for about $800. Should be able to do hoses for about $300.
It all depends on what you want to do and how much you want to spend.