BMW engine coolant in a grey plastic one litre bottle is about R60 per litre ( part number 82-15-2-912-152 ) . Drain your cooling system and fill with a 50:50 mix of coolant and water . ( Keep some for top ups if needed ) Change the mix every two years .
Oil is a bit more complicated .
What oil has been used before ? If a mineral base like Castrol GTX ( for example only ) has been used then you can't just throw in any synthetic oil .
If a synthetic oil has been used then you can't throw in a mineral base oil .
The two are not to be mixed .
The kilos of the car are also to be taken into account , no use putting a 5W-40 synthetic oil into a engine with 200 000 km on , the clearances in this engine will be large , a mineral base " High mileage " oil will work better here .
I also use Shell Helix Ultra , a 5W-40 synthetic oil , yes it is a bit of overkill but I like the startup protection .
Check your cars service history for the last oil service done and go from there .