That's too broad of a question... depends on the event, the type of people attending, how many and your budget.
Water bottles, beer coolers, pens etc... are all just junk in my opinion. They all get ditched fast. I see a lot of people hang on to keyring bottle openers if they're nice quality. They're not so expensive for good ones either. Depends on the market though, I wouldn't be giving them away to housewives for example. Flashlights and knives are pretty cool, but only if they're quality. Not the generic junk made in china mini swiss army knock off. But then those things aren't really representing your business in any way either.
If it's an event for climbers/tree companies then something they can use. A scrench, or a chainsaw multi tool would be high on the list, and not super expensive. Something to go in the truck, like those note holder things I see from time to time that stick on your dash. A small piece of climbing gear (carabiner) or if you've got some money to spend on bling then maybe a custom keyring tool, like a bar groove cleaner, or a tuning screwdriver, or similar.
If it's for customers, then something they will use is good. I send out calendars each year and get quite a bit of work from it. Could be a planting guide, or a tree/weed identification guide. People love stuff like that. I've given out printed flyers that had descriptions and images of the 5 most common invasive weed trees in my area and got plenty of work from that. Another thing I give away to customers who use me is weed killer. I put it in a spray bottle, and print a sticker with my company name and details, and 'super weed killer' on the bottle. Cost me about $1.50. People always ask whats in it, and I tell them it's my special made weed killer, not available anywhere else. They get a kick out of it. It's just generic glyphosate.
Shaun
