Yes, there are multiple flights from Singapore to Namibia for under S$ 2,301. The cheapest flight booked recently is on SWISS for just S$ 2,246, but on average you can expect to pay S$ 2,320.
There are no direct flights from Singapore to Namibia, but Cheapflights can provide you with all the information you need to find the fastest route with the fewest stops.
Departing from Singapore to Namibia will take you 39h. Both multi-stop and direct flights can be found to your destination and back.
SWISS, at S$ 2,246, was found to be the cheapest airline from Singapore to Namibia. An alternate airline flying to your destination would be Lufthansa.