You can get preset Pure Energy, Center Flag or Crossfire 88/4500 systems, with the regulator, for around $200. That includes the regulator and a fibre wrapped bottle. Adjustable systems will be more like $400 including the tank and reg, but do you need an adjustable system for a tippy?
Fibre wrapped tanks are generally better, because you can get 4500psi fibre bottles, but only 3000psi steel ones. And fibre-wrapped bottles are a good deal lighter than their steel equivalents.
Look at sites like paintballgear.com in the Nitrogen Systems section, and the preset systems you see for around $200 should be all you need.