If you are using Windows 10, and a current release of Sonar, WASAPI is the best choice for those without a hardware audio interface and the vendor supplied ASIO drivers.
If using Sonar X3, you may not be able to access WASAPI on Windows 10. I have found that WDM works OK in this case.
Some Cakewalk standalone instruments also demand ASIO only, and WASAPI is not an option. Some examples are Rapture Session, Cakewalk Pro, Rapture, etc.
I also have a Win 10 laptop with ASIO4ALL installed with no problems, but it is not my main DAW, and I am not attempting to connect an external audio interface. Not attempting any recording with this rig either! It seems to run fine with playback using virtual instruments or audio only using the internal Realtek audio chip.
I think that the advice to get a real interface is best, especially if you are serious about making music on your computer. The advantages to having proper low latency ASIO drivers, as well as the ability to record with your microphones or guitars using a proper preamp are priceless. The entry level units are budget friendly, and should be the highest priority investment after purchasing your computer.