i am totally hopeless with money. i alwys go out and buy supplies only to come home and find out i have them, or buy too much of something. i don't have a huge stash either, so i have to buy lots of stuff specifically for swaps. for a regular sized swap (not a mini one) i usually spend between $40-60 on everything including supplies and shipping (this is aussie dollars though and the australian postal service is a f***ing ripoff!!!). i also basically never get paired up with anybody even in the southern hemisphere (i always ask - but usually no-one signs up from my end of the earth). if i can keep the package flat and under 500g i can save between $5-15 on postage too, which is good.
the most i ever spent on a package was about $80 but that was because the shipping was like $50