It is still not clear what you want to build, but looking at the parts, it seems a bit complicated since you do not want to use premade modules. Your 2x25watt stereo amp is complicated and has a lot of huge capacitors. Considering all this, your board size is gonna be more than 10x10cm and the production cost is gonna increase drastically if you want to produce the boards in small quantities.
All the parts you mentioned will cost between 40-50$ and the PCBs will cost around 40$ for 10(cheaper if you get more). It would help if you could tell me about your project in more detail so that I may be able to help you.