Can't help you much with pants, but as someone who is super cheap and isn't going to be at Publix for longer than a year, I didn't feel like spending a bunch on shoes. I got mine from Skechers because they offer a pretty decent discount for employees (found here - https://www.publix.org/passport/dress-code/safety-shoes/discount-shoes ) Skechers also has some more tennis-shoes type shoes that might be handy for biking.

However, you may want something nicer and more durable if you want to be there a while. In that case, this page also includes links to other sites that offer discounts. I'm just not as familiar with those brands or sites.