SG001

@Steve87 will be in durban over the next couple weeks... contact him

Let's say that a grid-tied system is one that supplements your grid feed with power from PV panels. There is no storage, just supplementing. You've already said "solar in the day and Eskom at night", so I think we are talking about the same thing.

Such a system will reduce your bill, but won't give you protection against load shedding. 

For protection against load shedding you need a store of energy you can fall back on. In a home this is batteries. So the talk now switches to how you charge those batteries, how much battery you need, and your budget. 

Your loads don't sound high, but you should try to quantify them so that you can calculate how much stored energy you need for a 2 hour outage, a 4 hour outage, > 4 hours. 

Make sure you include EVERYTHING you need backed up. Presumably you have a wifi device and/or a fibre interface that needs to be backed up. Include it all, add it all up.

You should get a system with a pure sine wave output since you are going to be powering motors. Modified sine wave systems are not recommended when you want to power motors.

You're probably going to need to split the DB so that there are backed up and non-backed up circuits. This is common. Without this the geyser will turn on, the oven will come into use, and your battery will discharge very quickly. Or something is left plugged in and again you are backing up more than anticipated.

So you need an inverter and batteries. That won't save you money on your electricity bill since you are still going to be using the same amount of electricity (maybe a little more, but not a huge amount), but it will give you back up power at any time of day. You can add PV later.  PV is what saves money.

Prices... well, try to figure out what the load you need to back up is (see above). There are two ways of looking at this. The average, constant load, and the peak load which will occur when devices start up (EG the motor in your fridge). The first gives an idea of how much battery you need, the second gives the upper limit of the current the inverter needs to supply.

I'd suggest buying more than you think you'll need if you can afford it. Loadshedding is going to be with us for some time, and it is very nice to have lights on, to be able to make a cup of coffee and so on.