I have a broken leg, so I’m using crutches. I have to do some grocery shopping. When alone, I need the help of staff to help carry bags into the car. Is it necessary to tip the guy who carries the bag for you? and how much?

I’m trying to be more environmentally freindly, so I want to reuse plastic bags when I go compras.Tengo usable lot in my car trunk, and when it hits stores, I never remember them out! Please give me some tips on how I can remember when I leave the car, thanks.