Since people may be interested in the process of building an embedded product (a simple one) it usually goes something like this (that I have been involved in):

Since people may be interested in the process of building an embedded product (a simple one) it usually goes something like this (that I have been involved in): 1. Buy a dev board closest to your product desires. 2. Modify the board as needed and get some of the features working, while laying out a PCB. 3. Design the PCB and simulate as much of the hardware as possible. 4. Send out a board revision with all sorts of test points and such, including parts for experimental stuff. Jumpers are good to add at this point to, so that certain parts can be tested independent of the rest. (this is expensive, think 1-5k for a small run of small boards) 5. Order all the parts, if the board is using a lot of surface mount (SMD) you do not want to be hand soldering, so order a stencil too (for laying the solder paste). Parts will be expensive since you need rolls to feed into a pick and place machine, stencil will be around $300-400 for a good quality one. 6. Build the boards. 7. Test them and find all the problems and errors. 8. Go back to step 3 until the board mostly works. Software development will continue throughout the whole process. If you are good and able to keep the revs to a minimum, and the board is small it can still be relatively inexpensive. But if you plan to sell it, regulatory certifications (FCC, UL) can be another problem since they are slow and expensive. Hope that was useful. Now remember this is the process I have been involved in and others may do it differently, such as when parts are very expensive more simulation is done. If you are doing something very simple or piecing together boards you may be able to get away with breadboard prototyping most of it.