I currently charge 48 a flat of petunias, 64 a flat of zinnia an marrigold, and pansies which are our winter color, (god help us but that is about it) is 50 a flat.
This is about 200% above what it costs me, and sometimes if I get motivated several month before when I need the flowers and grow them myself it is over 1000%.
I can grow a flat of marigolds for less than a buck.
You have to take in to consideration that the beds will have to be cleaned up and cultivated before you plant in them. I haven't fond one were i could just jam flower in and go. So you need to charge for that too
I charge $36 a flat of 36 this is for pansies and most other annuals or perrenials i include a bag of tosoil 98 cents and mulch 1 bag will cover 2 flats at $2.89 per bag the plants cost $6 to $7 a flat is this what your talking about ALPINE.I can plant 10 to 12 flats per hour.