For a lightweight, portable antenna (I have my share of those in a camping container) I've often used old 35mm film containers (plastic) with holes drilled through opposite sides. At first I was highly skeptical they'd be strong enough to support anything, but Pete KT2B who was an avid photographer (for a living) showed me he was using them to support the ends of a full-sized 160m dipole temporarily installed for the ARRL 160m contest and the damned thing stayed up all weekend! That's an amazing amount of stress (including probably 50' of coax hanging from its center) and the little plastic film cans worked. Cost = $0 since he (and I) had hundreds of them laying around. Remember the secret word from the film The Graduate? "Plastic."