The Raptor is probably the most expandable heli out there. There are tons of after-market parts. A typical kit-only price is $280.

One cheaper, less expandable, but just as flyable, is the Century Hawk Sport. I fly one and like it a lot. Typical kit-only price $160.

I had one bad crash where the cost of replacement parts was the same as a whole kit. So I bought a whole kit. As a crashing beginner, I really appreciate the cost-of-a-crash cieling being less than $200. And now have spare parts, from the replacement kit, that have already come in handy.

-Mark