You would need to check the individual rules/laws in your country and/or state. I know that in the UK you'd be on dodgy ground if, for example, you ran a raffle or lottery for an item that had monetary value without the appropriate licence or exemption. You could give away materia, or something that was unavailable for cash, but not (for example) Fantasia.

It's a minefield to be honest & everywhere has different laws, some incredibly strict. Best to ask the relevant governing body. =(