A search on ebay, only came up with this alternative - Pegasus PG6507 – Large Cacti Plastic Model Kit – 13 – 50 mm, still not cheap, but as a kit can be put together in different ways. surprised there are no cheap Chinese ones, as there are plenty of palm trees available!
There is another Pegasus kit, which looks cheaper, set number 2.just search on Pegasus cactus
Narrow gauge Francophile interested in 1m, 60cm,50cm , 40cm and smaller gauges . Build in scales from 1/6th to 1/24th. Also 1/32nd and 1/35th using 16.5mm track to represent 50cm and 60cm gauges. http://www.rue-d-etropal.com