It may surprise people but some of the lesser trusted brands actually keep their value very well.
For example the 2010 Kia Cerato 2.0 kept 77.6% of it's value after one year according to the Auto Dealers’ Guide.
That's better than the :
Alfa Romeo 159 1.9 JTS: (R303 500) R195 300 - 64.3%
Citroen C3 1.6: (R148 500) R94 700 - 63.8%
Citroen C4 1.6: (R185 000) R130 300 - 70.4%
Dodge Caliber 1.8: (R206 900) R154 800 - 74.8%
Fiat Bravo 1.4 T-Jet: (R252 100) R192 500 - 76.4%
Ford Focus 1.8: (R196 910) R148 400 - 75.4%
Jeep Grand Cherokee 3.0 CRD: (R517 126) R393 500 - 76.1%
Mazda3 1.6: (R236 440) R180 100 - 76.2%
Mitsubishi Lancer 2.0: (R241 413) R179 700 - 74.4%
Mini Cooper 1.6S: (R290 723) R221 900 - 76.3%
Nissan Xtrail 2.0 4x2: (R288 900) R218 800 - 75.7%
Peugeot 308 1.6: (R197 500) R145 900 - 73.9%
Renault Clio 1.2 Va Va Voom: (R117 000) R86 800 - 74.2%
Ssangyong Actyon XDi 4x4: (R259 995) R185 500 - 71.3%
Subaru Forester 2.5: (R314 000) R243 000 - 77.4%
Suzuki Grand Vitara 2.4: (R322 900) R246 500 - 76.3%
Tata Indica 1.4: (R89 995) R66 900 - 74.3%
Toyota Yaris T3: (R171 500) R130 600 - 76.2%
Volvo C30 T5: R308 000 (R234 700) - 76.2%
The trusted Toyota Corolla 1.6 only kept 78.3% of it's value which is a whopping 0.9% better than the Kia Cerato 2.0.
Source:
http://www.iol.co.za/motoring/industry-news/resale-values-we-name-best-and-worst-1.1017906
If you can barely afford the car then I'd recommend buying something else or second hand.
Make sure you don't forget to factor in insurance which is usually over R1000 per month for a "performance vehicle".
It seems as if insurance companies regard anything larger than 1600cc as a performance vehicle.