ideas for icons please

Howdy, i'm working on a project that requires icons for the following meanings.

Anyone with a good idea for any of the following reply below please.

Expensive - at the moment i'm using a wad of notes.

Cheap - at the moment i'm using a pile of coins.

Free - this is the one i'm most stuck on.

Already owned by the company - this is going to be their logo.

size will be 24x24.

Thanks in advance.

Not easy at 24 x 24.
How about keys. Gold and silver and then an empty outline of a key for the free one.
Or perhaps money jars (or some sort of container) One full, one half full and one empty.

thanks for the suggestions.
The money jar suggestion is similar to one i had of a hand with pound notes in and a hand with coins in then a hand with nothing in. The problem is you waste alot of space with the hand making the things in the hand hard to clearly work out what they are.
The keys one isn't bad or just padlocks gold, bronze and unlocked padlocks.

Any more anyone?

How about Palace, House, Tent : Plane, Car, man walking : or comparisons along those lines.

The padlock idea is not bad. I'd go with that, personally...