How to keep my beachy waves from falling flat?

I have really thick, coarse, frizzy, wavy hair. It's a bit below my shoulders. I was always a huge proponent of straightening it and hated it to get the slightest bit damp because the waves would start. Over the past 6 months I have been doing the beachy wave look with the curling iron and love it! I still have to straighten it to get the frizz out but don't OVER straighten it and then curl it. Problem is, I have never liked having product like hairspray or gel in my hair because it was crunchy or greasy or made my head itch. However, my waves don't stay in for very long before falling flat due to no product. Iv'e tried the sea salt spray but that was crunchy and made my head itch. Is there anything I can use that is VERY lightweight but holds?