For those interested, I received the quote from UWELLPCB for 100 pcs. 4.250"x3.000" boards with them supplying and installing about 50 SMD capacitors/resistors/inductors (mostly 805), 2 SOIC-8, 2 SOIC-16 plus a through-hole crystal and a 40-pin DIP socket. They will cost about $22.50 each which includes fabricating the boards, buying and installing the components and air courier charges. I can reduce that more by giving them an annual order from which they will release monthly shipments.

I have a stencil for the solder paste and have been assembling these myself, inserting the components with tweezers. The last batch of four took 2 hours or 30 minutes per board. The bare boards cost me about $4 each (from PCBCart) and the components about $8 per board. Their prices seem very reasonable to me and fit within my price structure for the product.