is dhp an expensive kind of tea/oolong?

It's partially expensive because it's famous / prestigious, and also because "genuine" (whatever that means) DHP is fairly rare.
By genuine, I roughly mean tea that actually comes from the "scenic area"（正岩 in Chinese, maybe?) and is from first or second generation clippings of the original bushes.

As far as traditionally processed (i.e., high charcoal roast, decent amount of oxidation) Da Hong Pao, especially if it's fully or partially hand-processed, it's probably trickier to make than some other teas, and if the tea leaves are actually rare, more care has to be taken in handling / processing them, and they might be processed in smaller batches. I think, though, that other hand-processed yan cha also tend to command a high price, and of course it's very easy to find cheap "Da Hong Pao" as long as you don't really care that much about what it is. I am pretty sure that (other than amount of oxidation / firing, and the amount of work that's done by hand), processing for yancha is generally about the same, though more care might be taken with more valuable maocha.

It's been suggested in several places (e.g., http://amateursdethechinois.blogspot.co … oct-2.html and Charlie's post at http://www.teachat.com/viewtopic.php?p= … cd6#72583) that much of the tea actually sold as DHP is a blend of some other teas. In terms of "what's the real Da Hong Pao", it's also worth having at least a quick read of what Guang of Hou De has to say at http://houdeblog.com/?p=111. I would be really interested if some of our translators (cough-cough) would be able to do some further research on this subject (time-permitting, of course). Whether they're the real "Da Hong Pao" or not, I have enjoyed many of the Bei Dou #1s that I have tried.

By the way, the Da Hong Pao that I got in Wuyishan was not (by far) the most expensive tea that I tried at the factories I visited. Bai Ji Guan and some other teas were the most expensive, at around 3500-4000 RMB / jin (roughly $5-600 US / 500g at the exchange rates a year ago). Da Hong Pao was mostly between 500 and 800 RMB/jin, though I wasn't really blown away with any of the ones I tried.

In any case, I think it's probably true that a lot of what's sold as Da Hong Pao isn't entirely what it's said to be. But in cases where it is, I do think that some of these factors play a role in its price.

i was looking at getting some dhp and i did not even look at the price but when it was time to pay, i got a rude awakening!  it was 45 canadian dollars for 4 oz.  the guy only had one kind of dhp, he said that it was his highest grade.  i told him that i would get the tea later since i have so many other tea to finish anyways. 

imo, dhp is a bit similar too some of the wuyi oolongs out there.  i will get some dhp from this guy.  dhp is not one of my favourite teas but just something to have at home, to change up the flavours....can't drink pu erh tea 24/7.  can you?

thanks for the replies guys!!

I agree. This has been the case for DHP, long jing, bi luo chun, puerh... in my opinion all over-priced in their market average prices. Same is happening on TGY. I don't hope to see the same happen to dan cong or southern Fujian shui xian in near future. But, who knows.