I've been thinking about getting one to cool down my backyard during BBQs. Are these effective? Durable? I remember getting sprayed by these at Universal Studios in Florida during those hot afternoons and they felt real good. But those are probably industrial strength and very expensive. I'm looking at the kind you can use at home. I saw one at Walmart for about $80. I don't know if they can be found any cheaper. I'd appreciate any comments you may have on this.