seed propagation questions

I have been looking on the web for info about growing my first crop for more seeds. I have 3 healthy plants 2 girls and 1 boy 2 weeks into flower. I am not killing the boy because i want more seedes. I payed $110.00 American dollars for 10 seeds. Am I guaranteed (for the most part) to get seeds of the same quality? Is there a generalized formula to roughly predict how many seeds i will get? Will the weed still be worth smoking? Any other info on seed propigation is welcome and appreciated! Thanx for reading!

Just pollinate a small bud and you will get 50 seeds or so. You dont have to do the whole plant.

If I get (around) 50 seeds/bud i think that equals.........a shit ton of seeds/plant! awsome! I want to get enough to plant alot of them all around town.