Flyer/mailer cost question

so i have been reading all the marketing posts i can find on here and there’s tons of good info.
obviously flyer/mail campaigns can work and the key ingredients seem to be:
a good design
a good offer
good timing
good targeting
lots and lots of flyers
repeat repeat repeat repeat

one thing i haven’t seen much about is the cost of the individual piece and how much or little that affects the result.

what i mean is:

here in winnipeg in my area there are 2 very successful realtors that use flyer/mailers very differently.

agent 1 pays students to photograph every house (30,000) have the photos printed, then mounted on a full colour letter sized page with his photo, logo and year at glance calendar. it is laminated, has magnets on the back and is delivered to your door ready to go on your fridge every summer.

agent 2 mails 30,000 3.5x8.5 cards in full colour printed 1 side only every 2 weeks.

can anyone give input on different types and costs of delivered pieces and what effect it had on their results?