Most chip companies don't publish prices because they are useless to most of their customers. And by "customers", I mean people that buy chips in volume. For example, TI publishes prices at 1,000 units per year. If I buy more than that, I can get a better price-- and most manufacturers will buy more than 1k/year. But on top of the normal volume discount, I can negotiate a better price. Let's say that I want 1k/year of a part, I can usually get 5k/year pricing. I could also make a case for a "package deal", where if I need 1k/year each of 5 different chips then I could request 5k/year pricing on everything.
In the end, the price on the web site is almost never the price that I actually pay. Further, the price I pay is almost never the price that you will pay. Maybe you got a better price, or maybe I did. Either way, TI doesn't want us to know each others price because then we could use that as leverage to get a lower price.
The other thing is that these chip companies don't make any money selling small quantities. Their overhead is quite large, and they need customers buying large quantities at a time. The point is, they have no motivation to sell direct to the small customer. That's why there are places like Digikey. Digikey will buy large lots, divide them up, and sell them 1 or 10 at a time.
Some chip companies know that selling small qty is a loosing proposition, and they are actually better off giving them away-- if in "good will credit" if not actual money. That's what Maxim, National, TI, and Microchip do. TI actually contracted with Digikey for their sample program. If you ask for samples from TI, Digikey will be the one to ship it to you.
So, when buying specialized components in small qty you'll frequently be out of luck. The chip manufacturers won't sell it to you, and probably won't sample it either. The wholesale distributors won't talk with you for similar reasons. And Digikey and places like that won't help either.
One thing to look for is each manufacturer will list, somewhere, places that sell their parts. Sometimes it's a link off of the individual chip's page, or sometimes it is somewhere else. But check out that list. Most of those suppliers will be wholesalers who won't talk to you, but they might mention places like Digikey or Mouser. Failing that, you could email their main sales people and just be up-front about what you're doing and how much you will be buying and ask them where you should go to buy it.
C: definitely the assembly shop, if you have the wallet for it. That's for you to decide. Ask some quotes, and decide if doing it yourself is worth the effort. Since this is a hobby project you may think your time is free, but then it has to stay fun as well, hasn't it?
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Just got this in a mailing from DesignSpark: fundraising may get you started to have it done by a shop. Erik raised 313 218 dollar for a 5 000 dollar target.
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Alternatively, B: Again, get a quote for a stencil. Yet, even applying the solder paste manually will take less time than hand soldering, which I would not recommend: the resistors and capacitors are not much of a problem, but the ICs may take quite some time if you want to do it proper, i.e. all pins soldered and no short-circuits.
Not A: it takes too long and it's messy. I would only do it myself if I could use the oven.
Remember that Jobs and the Woz also hand-assembled their first batch of Apple computers :-)
Best Answer
(This is not legal advice, just my understanding as someone who deals with this stuff professionally).
If something is ITAR controlled you must not export it (or even detailed documentation regarding it) without the proper paperwork (probably a permit). Some kinds of sensors and other things are covered, as well as actual munitions. Likely if you're dealing with that sort of thing (precision inertial guidance systems, space-related technology, night vision technology, etc.) you'd probably already know it. Even if you import something from a country A you can't necessarily send it back to country A for repair without proper documentation. Handing a sensor across the table at Denny's in Idaho to the wrong person could land you in jail, as a deemed export. Sending your drawings for a quote could be a big mistake. Silly, perhaps but the potential penalties are severe (premeditated murder might be treated more lightly than an infraction). That's the US State Department.
There are also restrictions imposed by the US Commerce Department which may target specific companies or items based on what they are, who they are, or the end use.
Big companies tend to have a compliance department that deals with this.
In practice, ordinary bits like MCUs and such like are not a problem, and in fact can probably be procured more cheaply in China than sending them yourself (I tend to worry more about the quality of passives). High end FPGAs might be an issue, as well as things that can be used to build high-end radar systems and wide dynamic range accelerometers.