There is one called Estorac that is near Campredo, very cheap - we paid 5cents for lettuice plants. Can't remember the rest of the prices but extremely cheap.

To get there:
From Tortosa head for L'Aldea. At the last roundabout (where there is a low building with a huge red brick chimney) take the 2nd exit (the 3rd is the dual carriage way) it has a big no entry sign which is a bit confusing as it isn't no entry. Keep going on this road, it follows the canal. You come to a 'Finca privada' sign and have to go right. At the end of that stretch you come to a T (it's not far) turn left.
Keep going until you will find 'Plantas Estorac', a big white building on the right hand side.

Nigel