I'm valuing my time at $5/hr, as a limiting factor! (So I don't end up taking on an unrealistic amount of work if a bunch of people are super into this...)
Every letter I send costs $1 CAD -- more, if the letter is too thick, but I don't know how much more.
A package will probably cost more like $8-$10, at least within North America.
If I spend 10 minutes per letter (okay let's call it 12 minutes), each letter costs $2. At two letters/month (1/month seems too infrequent), that's $4/month or $48/year, a bit more than my twitter estimate. Also you'd have to pay for all your outbound postage! And this is without materials! I have access to Shelley (@UhWhatsHisFace on twitter) who's really into the idea of making cool stuff for this. Luckily she's great at making things out of nothing but paper, so maybe add $.50 per letter?
My final Bare Minimum Estimate cost to me: $5/month, $60/year. (per player)
This is probably around how much I'd charge to play the game. Too much?
letters sent via canada post cost a little under $1 CAD.
how much do letters cost to send out of where you live?
i would like to send frequent letters, but that will get expensive. if the game is multiplayer and runs on phases, sending out letters at fastest once a week and at slowest once a month sounds practical. if it is single-player, it does not really matter.
i would *love* to send small packages and game-relevant oddities, but they will be even more expensive.
i am considering offering a few price tiers: cheaper for those happy to receive basic letters, more expensive for those interested in receiving more interesting things in the mail...
i am (very cautiously) considering doing some parts of this online and saving the physical letters for a specific part of the game, but i think this is a bad idea.