Years ago when CB's were booming I started doing a part time business from home. Didin't take me long to figure out a $100.oo invested in a radio that I could sell for $110.oo once or twice a year; wasn't as good as a
$30.oo microphone I could sell for $40.oo 5 or 6 times a year.
Picking something that you like is going to be beneficial in the long run... just make sure you can make money at it.. Most sales people are poor at their job, the ones that are successful and have repeat customers are the ones that know what they are talking about. I suggest going to school and then you can do both jobs.
Keep your overhead and inventory low and work for yourself ( no employees)
This is where I am. I fix forklifts, I have a van, stocked with inventory and I use my garage at my house. I make good money, I may not be a millionaire, but so what. I have fun every day! Make sure you keep enough inventory that you can do the job.