I am doing more and more research, as much as possible that is closely related to the climate in South Africa, found that these are suggested for beginners...

Trees that I recommend for beginners are:

Olea europa var. afr.(Wild Olive}. These are evergreen and hardy; the leaves miniaturise very well; they sprout an abundance of new branches on hard wood; they can be obtained from nurseries, grown from cuttings and dug from the wild.
Ulmus parvifolia (Chinese Elm) - a deciduous tree, delightful in spring when it gets its new foliage. As with the Olive, leaves miniaturise well and it breaks back well on hard wood. Available from nurseries; I have had a great deal of success with root cuttings and air layering.
Ficus natalensis (Natal wild fig) - ideal for root over rock style. It is very flexible, can easily be wired and sets in position very quicckly. It is one of the few subjects that one can actually notice increasing in girth in a bonsai pot. It grows well from heavy cuttings rooting within 5-8weeks in summer.

My plan is not to buy anything until Spring time in a few months, which will give me time to do as much research as possible, locate suppliers, etc, etc.