300 dollar engine...I think if you adjusted for inflation, from today to say 1958 that would be the price of a Dooling 29! In real terns the cost of engines has come down. What has changed is that wages have not kept pace with inflation since R.R. was in the White House. So, we don't want to spend the money to get a 300 dollars engine, now, but as Eric states, using it for 18 years it would pay for it's self.
Oh, the best combat engine of the 1990's was the Fox Mk-VII! Mine ran circles around the Nelsons; even the custom Nelsons like the ones Mike Wilcox was using. Nothing could come close, and all that for 150 dollars each. Oh, then the chrome came off the liners, and they were done. So, I to when to Nelsons and after some long talks to my friend Gary Harris and to Glenn Dye, I got them to run like my Fox's. But they did not come out of the box ready to run, and they cost 265 each. The chrome did stay on the liners, and the cranks held up, but the bearing in back was only good for about 75 runs, and it was not a cheap bearing. So, in the end, it was something of a toss up on the great combat engines debate.
So for 15 carrier I think 200 is a fair price. 300 is probably more than I would spend, but not out of the question. It has to be a good runner out of the box though. I don't want to have to re-fit every part like my Tower 40 or my Enya SS-15.