use an amulet coin on a Pokemon in a trainer battles
in gold there are lots of different types also the legendary pokemon moltres plus trainer blue
there is lots of max elixers you can find them out in the wild i dont know if you can buy them
if you want to get lots of money well,do the Pokemon league
BATTLE
in lots of places. lol
Lots and lots this should help: http://www.serebii.net/mysteriousdungeon/dungeon/22.shtml
in many dungeons there are lots of items, the blue gummies are everywhere
I battle
there are lots so i cant tell u all of them but there is a lot (hope this helps)
There are many ways to get a Pokemon to like you more, depending on which version you use... In Red, Yellow and Blue it doesn't matter.... In Emerald, Ruby, and Saphire you can give it a Soothe Bell or use lots of items (i.e. protein). In Crystal, Silver, and Gold use lots of items on it and give it haircuts(in the basement at Goldenrod).
you find lots of shelgons after you defeat artucuno.
You can't directly find lots of money.. I would suggest beating the Elite Four a couple of times, it will net you some