Public Planters

Hi, Please can anyone help me - Joe especially?

I'm part of a local community group and one of my areas, as keen buit essentially amateur gardener is to do something with our planters on our high street.  We have two types, Type 1 hexagonal, teak with metal corner posts, approx 57 cm high (external) x 53 cm (interna)l on each side.  Type 2 = plastic, square (all internal) 93cm w x 93 cm d x 21 cm d.  These are located T1 = 6 x East facing, 1 x west facing, T2 = 6 x South facing.  Please can you advise on budget planting for year round interest at minimal cost?  Thanks very much.  Don't know if this is relevant, but we have as a community group also bid for the Mary Portas Pilot HMG scheme for our village.  We are desperate to save our high street and after a 'street day' on friday 16th the planters were a definite theme of what we could do to make our village look 'less unloved'.  Please help us save our high ~St and with it our community?  Thanks very much again.  Love Lancing x