How much green? Up to two W, I would use a single 2W DPSS for approx $1,000. Above 2W, then one wave plate and a PBS (laser line for 532 works much better than broad band) for $50 + $100 and two 1.5 or 2.0 W DPSS lasers for approx $2,200. For more, go with the plate and cube and combine as the price begins to skyrocket /watt.