Rhett - As Jack said, each item gets it's own tickets, so things that are less value people might only throw in a ticket or two. Bigger items obviously attract more tickets. This allows people to only get what they want, buy tickets based on the number of things they want, and gets people to consider the total number of things we have when figuring out how many tickets to buy. I'm not saying there may not be a better way, but this way seems to work quite well for the people winning things (most people get stuff they actually want) and, as long as we have a good pool of items to raffle, we shouldn't have a problem selling tickets.
Over the years we've tried out a few different methods and randomly raffling things from a single pool of tickets was definitely not the way to go. Thanks for the suggestion.