Ballpark figure.....AFAIR, I got my first batch of quails from a former officemate of a close friend at P 40-50/quail which I think was actually a steal for that price. So, for 500 quails, that would be P 25,000. Hindi ko na alam kung magkano ang quail ngayun. Materials for building a pen...hidi ko na matandaan. Lot area ko, 600sqm. Price per egg would depend on the production costs.
If you want more info on quail rausing and how to build the pen, try going to these links (I hope they still work or are updated):
Oh, I also paid a visit to UPLB to do research on everything and anything about quails. UPLB has a lot of materials for sale for quail raising. These would be invaluable of you want to go into this business.
ARB: you can go to UPLB's website so that you can browse the material that they have. Pwede ka din mag-order on-line. I'l try to look for whatever materials that I might have pag balik ko sa atin dyan sa 'Pinas. Right now kasi, nasa over-seas assignment ako. Can't promise aything though: last time I saw those materials was 4-6 years ago.