Difference between SmartPlan and SmartSaver?

[catharsis]

Hi
I'm currently on a month to month basis after my contract expired. Looking to hold to my S5 as its still in good nick.
Telkom has the Splan and Ssaver options which look very similar with both going for R99 for Saver/Plan100.

Id like to know what the fundamental difference is? I know that only 150mb of data is offered and you need to take a device if you want the additional 1GB every month.

Can more data be purchased and at what cost? 500mb should be sufficient.

https://secure.telkom.co.za/today/shop/personal/plan/smartplan-100/
https://secure.telkom.co.za/today/shop/personal/plan/smartsaver-100/

TIA

 

[catharsis]

This would be a great deal if you're looking to keep your current device:

http://mybroadband.co.za/news/cellular/111702-great-value-with-new-r99-telkom-mobile-deal.html

Closest Telkom currently has to this is a Galaxy J1 for R199. Sell the phone and keep your current device.
Will telkom allow this?

 

[catharsis]

Smartsaver works like. Topup allowing you to add data/minutes.

Smartplan is limited to what you can add in case your cap runs out.

But smarplan offers the WiFi and Telkom calls facility.