Is it common for tubes to outweigh the cost of the amp or preamp?


I just got my first tube (headphone) amp and was wondering if it is common to spend more on the tubes than the actual cost of the amp. The amp was $599 with stock tubes. I just ordered NOS driver tubes that ran $640 for the pair and the power tube upgrade I'm planning will be another $300. That has the tubes sitting at 1.5 times the cost of the amp itself.

I don't find the total of $1539 for the amp and upgraded tubes unreasonable but considering the next model (amp) up is $1199, it has me wondering what would be better... a lower cost amp with superior tubes or a higher cost amp with stock tubes?
samiamnot
After some listening I am very happy with the purchase. From minute one, before any warming up or burning in, I noticed a significant improvement.

The new tubes have added so much detail to the highs and tightened up the low end which is resulting in a much bigger soundstage. They've given my HD820's a soundstage more comparable to how my HD800's were sounding with the stock tubes while still retaining the more full sound of the 820's. I'm also not experiencing the listening fatigue with my 820's like how I was with the stock tubes. I can listen to them for hours without a break now like I could before with my 800's.

Were they worth $640? For me, yes, and here's why. They are rated to last up to 15k hours so that comes to $0.04 per hour of listening. My turntable cartridge cost me $600 and is rated to last up to 2k hours which comes to $0.30 per hour of listening. So even if the tubes died after 2133 hours, that'd come to the same $0.30 per hour cost as my turntable cartridge. It was totally worth it for the improvement in sound I got when upgrading my cartridge. The improvement in sound from the upgraded tubes is just as significant and much cheaper when it comes to dollar per hour value. 

I look at tubes in the same light as my turntable cartridge. Better cartridges/tubes equate to better sound, and both wear out and need replacing so you're essentially paying by the hour with stuff like that. Considering it comes out to pennies on the dollar, I'd rather have a superior listening experience than pinch pennies and get subpar sound.
I would NEVER spend more on tubes than the amp cost. There are plenty of modern tubes that sound perfectly fine. The real issue is with driver and preamp/phono amp tubes and that is noise. RAM Labs has super low noise versions of many of these. I have his super low noise 6922s in my Audio Research PH 3 SE and boy are they super low noise.
Very impressive. He goes through 100s of tubes and hand selects the ones with the lowest noise. His tubes have easily half the noise that my NOS Telefunkens did which I have already sold so don't get horny.
@samiamnot- KUDOS, on your experimentation and learning experience. Now- simply enjoy the fruit of those (listening pleasure) and ignore the noise of the naysayers/cheapskates.
@mijostyn Thanks. I'll look into those tubes. I'll be moving the NOS Siemens & Halske' to the WA2 next year when I do that upgrade which will leave two empty sockets in the WA3. Might give the RAM Labs a test and shelf them for when I upgrade. It'd be awesome if they sounded almost as good or even better at 1/3 the cost.
@rodman99999  Thanks. I think I'll have saved in the end by going for the gusto from the start and nixing the upgrade bug. The worst is doing a moderate upgrade and feeling like you've sidestepped more than stepped up and just kind of wasted your money.

If it's within a comfortable budget and I know I'll most likely end up there anyway, might as well go big vs stepping up the tube upgrade ladder and spending money on tubes that'll be shelved long before their life is up. Like if I have superior tubes, I can't see myself being like "hey let's swap in those old tubes that don't sound as good for nostalgia sake."

I feel like I can consider my new tubes a good "reference" pair. They exceeded my expectations. Now I can get a cheaper pair and REALLY see/hear if they are just as good. I'm not sure that everybody who says the "holy grail" tubes are a waste of money have actually heard them because I am blown away. It curbed my craving to do a quick upgrade of the power tube right away at least.