Postbox Courier collate parcels. In other words, you can instruct them to delay delivery until you have a number of parcels and then ship.
Problem is, the more parcels there are, the higher the shipping, and I have never had anything shipped by them that wasn't R300 and over. Even one small parcel containing a phone cover was about R300.
Postbox-Courier is meant to be faster, about a week from shipping payment to actual delivery, but my group parcel from Hong Kong containing Christmas gifts I paid for on 15 Dec still hasn't arrived, and I'm pissed.
Aramex Global Shopper (AGS) charge R195 per 500g and R99 per 500g thereafter. If you have an FNB account you can get R75 off the shipping for each parcel you receive.
They clearly state where parcel is, and you can track using their page through both the AGS website and the Aramex express webpage. They also have two apps - their own AGS app, and the Shop & Ship app (as AGS is known as Shop & Ship internationally.)
AGS usually take 2 weeks to deliver, dependant on customs.
As per SARS customs rules, if your order is below R500, there is no duty applied. However, customs also do "spot checks", so sometimes your cheap parcel still gets delayed, and duty added.