Steve's Suit

A brown or grey, single breasted suit would go nicely with the pale gold wedding dress, and will not be too formal for the garden setting. Dress it up with waistcoat, tie and hanky/flower. Maybe a subtle pinstripe? And some dapper shoes of course...

These ones from Sergios:

Texas & Hartley suits
http://www.sergios.co.nz/suit-hire-suits-wedding.html
Approx $210 ea incl shirt, waistcoat, neck tie & hanky; $110 just for suit + $40 for waistcoat

Perhaps hire suit and waistcoat ($150), and buy Milano shirt and tie ($2-300?) so he still feels pretty?

Plus shoes..... (hmm, the budget for those could be infinite)