Love Mario Kart Brawl

My dad got me a wii for christmas last year and it’s been the best present ever. I love mario kart and play it all the time. My dad really likes guitar on rockband and my mom is always jumping around on the wii fit, its funny to watch. My brother and I like having friends over and playing with 4 people. I want to find a place where you can get nintendo game download as I want more games but my dad says they are too expensive. Does anyone know where I could download some good wii games?