Cheapest I have seen advertised http://www.soundsliveshop.com/p/Stagg_T ... SPSA1000BK
I have a pair with small 'as used' marks on them but still good condition - no rust and clean adjustable fitting.
£10 the pair £8 courier on mainland.
Don't need them anymore as I have Bose L1.
Oh, 1 plastic top insert missing but I will include it if I can find it. Chris.