Similar story for me during my college years. I worked nights and weekends in a small chain toy store at the local mall in my hometown in Pennsylvania for 3 1/2 years, making minimum wage. Stocking shelves, working the cash register, whatever I was asked to do. Averaged between 28-33 a hours a week during my entire time there. Sometimes went as long as three straight weeks without a day off if I go stuck with back-to-back Sunday shifts. I worked hard, did what I was told, and had a good relationship with the manager, assistant manager, and my co-workers. I got to the point where I was occasionally put in charge of the store if/when both the manager and asst. mgr. both took a night or a Sunday off, would close out the register, make the nightly bank deposit, etc.
After I graduated college, I had my first "career" job lined up in Connecticut, but would not be starting until September. So I had a final summer there. Around the same time, the owner of the store sold the chain to a larger chain, and we got gobbled up by a corporate entity. About half the employees were let go, but the manager and I and one other person were retained. I was 21, but when the new regional manager was looking to hire a new assistant manager after letting the old one go, he asked me what my post--college plans were. I think the job would have been mine if I wanted it, but I turned it down because I had my other job already waiting for me. They were still kind enough to allow me to spend my last summer there with a promotion (head cashier) and a 30% raise (from $3.35 an hour to $4.35 an hour).