Wanting to start Sewing Sewing Machines Parts and Sales in Los Angeles

Hello. I am a high school student, and for my senior project I am wanting to learn how to use a sewing machine. I have a huge interest in clothes and desire to learn how to do alterations/tailor clothing. I have no clue in which equipment to get. Can anyone here, recommend me a affordable sewing machine I can begin with? A specific thing I am wanting to use the sewing machine for is to taper jeans. (ex: make a pair of baggy jeans into a slim fitting jean)

I read some posts from the sidebar, but I am still confused. Any help would be greatly appreciated. Thank you.