could probably do better on your own. Silk plants are good, avoid plastic as they can tear up your bettas fins. They also dont like current - an air pump with a hang on filter in a 1.5 gallon is going to be very stressful for the betta.
If you needed to keep it simple / cheap - just get yourself a 1.5 gallon bowl, get a mini heater, set up some silk plants and call it a day.
If you felt more ambitious you could do the same with some live plants. There's some very cheap easy stuff that will live in very low light that will make your betta much happier and improve water quality drastically.
So, long story short - i wouldn't buy that kit. For $20 it is a good deal, but i wouldn't use a filter or an air pump in a 1.5 gallon tank.