Hello and welcome
It sounds like you take the same types of photos as I do. ...and like you are starting out the same way I did, on a budget! I think my biggest mistake was jumping in and buying too many manual prime lenses, just because the price was reasonable and I wanted to save money. BUT I was never REALLY happy manually focusing, it's just too hard when you are chasing kids and dogs around!
My house is pretty dim, and lighting always seemed to be a challenge, so I bought the AF360FGZ a couple months ago and I think I have mounted on my camera four times.
MUCH more useful has been my new FA 50mm 1.4... it hasn't left my camera since I got it. I can even take sharp photos in our den when it's darn near dark!
So...long story longer

I recommend the 50mm over the flash