I used to think amps where overpriced. But the more you look at it, the more you realize if every company involved in manufacturing, marketing, shipping, and sales (and if applicable customs) to get the amp to a local music dealer or your front door and still remain afloat, those companies aren't making much. You take the components used to make the products, while most are cheap, items like the chassis and transformers are not cheap.
Just think, transformers are iron plates (not cheap) strapped together then have thousands upon thousands of copper wire (copper is super expensive) winding in between the plates, held together with paper and glue between each layer. Just watch the making of a speaker voice coil, that is just one layer, a transformer will have that a couple hundred more times. Then take that and realize they are connected up to lead pins usually silver and tinned, if not having connectors on them, but the whole assembly is encased in a protective shell. The grand total of a transformer weight is a hodgepodge of solid iron, steel or ferrite, and copper, weighing on average 20lbs for a 120W output tranny and 400W power tranny. Since most companies don't make their own transformers, they buy from other companies, which have to make their profit, and the amp manufacture has to pay shipping, which isn't cheap considering their weight.
Then we talk about the fact that the wood construction on the amps are made from 8-13ply birch and hardwood is heavy and expensive. Most good manufactures dovetail the corners which is a skill all its own. And to top it off most manufactures have another third party vendor that manufactures and silk print and if applicable powder coat or chrome/anodize the chassis. Better chassis are welded at the edges which adds more to the cost. As they are also not light weight, the shipping cost of chassis is only tacking on the manufacture price.
After that is all said and done, the people on the assembly line need to be paid, the company needs a margin of profit to keep running, so they set that, its usually not much either, manufacture cost, plus a fixed percentage of that cost and that percentage usually applies to employee wages, all the company's costs (leasing the building, maintaining the equipment, upper management, marketing).
Then a little bit is added to the final price as the distributor has to pay the shipping. Now the average 120W amp weighs about 60lbs. Not cheap to ship and even more expensive when you ship out of the country as now you have customs fees, the original shipper has to fill out more paperwork (more time, more money). Shipping something that weighs that much to another country is or even continent is why American products are so damn expensive in Europe and especially Australia and vise versa.
So after the shipment reaches the distributor, the distributor will mark up the price not only to cover the price of the product, the shipping cost, possible customs fees, and will add their own cut to the profit as they have to make a profit for their business.
Then after ALL of that is done, it is bought and shipped off to either you or the music store. With the music store, they have to pay shipping, they have to mark up the price so that they can make a profit to pay the employees, marketing, business fees (utilities, lease, upper management etc) plus interest to keep the company growing.
If you where to buy online from a music company, you are paying their costs plus the shipping.
And then we forget the fact that the final cost includes warranty where most companies waive the shipping charges, to send it off to the nearest place (if not the manufacture) to get it fixed and sent back to you free of charge. Also realize that the bench techs that fix amps like that are paid $20 an hour in the US, more depending on where you are at in Europe.
Its then not so far fetched to see why an amp that originally cost the manufacture 300-400 USD to build, to cost about 900-1000 USD at the music store.
The reason cars are so cheap, is that they are mass produced and not shipped very far, there is no middle men and no third party shipping company. Cars are actually more mass produced that guitar amps and have much faster, more efficient technology. Because of this, the margin of profit to the manufacture can be much less. To top it off, the supply and demand curves for vehicles exceeds the demand for guitar amps. If supply is much higher than the demand relative to the supply of guitar amps, the final price, is going to be lower for a car than a guitar amp, regardless of how much it costs to manufacture.
Yes the companies involved want to achieve as much profit as possible. They will get their margin of profit as high as they can get for a certain population that is willing to pay. The more they charge extra, the more stable to company is, the longer they will be around, and the more stable their prices will be when the economy shifts during low seasons or years. Basically everything Jind said. They know you will pay it, because to you its worth it. Still the price to manufacture a guitar amp, is still not cheap. Back when I was wanting to build my own amp, I found out real quick, its not a cheaper way to go. You will end up spending more money building your own, so if you want to save, go buy one in the store. If you don't care about price and want the experience of building your own, then go that route.
I am still surprised that companies like Peavey can sell Windors for the price that they do and still make any profit off of it.