Although I do own a BonTon for North, I only use it for special adventures (think long, daytime walks when we're destination-bound for Baker Beach or Crissy Field). On his quick, prework potty breaks and late-night, before-bed jaunts around my block, I simply reuse plastic bags from the grocery store. When I'm planning a Whole Foods run, I grab the reusable tote that's stored in my car, but for quick, run-ins, I ask for plastic knowing North can reuse it.
In order not to continually find chaos when I open the storage cabinet under the sink, I picked up this Rationell Variera plastic-bag dispenser from IKEA for just $1.99. That way if I need to grab a bag for North's business or to tote snacks to the office, I now have an easy go-to spot.