Bikes are much better today than in years past.  I would never advise a Walmart or Crappy Tire bike, but there are some nice "urban" bikes out there at real bike stores that will shift incredibly well and will last, without being magnets for bike thieves.

Here's the sort of thing I envision for you in an Opus, which is a small Canadian manufacturer that makes a decent bike at a good price point, but there are lots of bike companies out there:

Something like this with a comfortable seat, tires of a decent width and tread, and a quality 7 or 8-speed cassette (competition bikes are 9 or 10-speed) is what you're looking for.  You can get bikes like this with a suspension fork or a rigid fork.

I don't know what your local stores carry, but anything by a reputable bike company will outperform and outlast anything from a big box store.  Take a few for a spin and see what you like.

I agree that it is best to get a good quality bike from a reputable dealer.

I have a Schwinn that cost more than I thought I'd pay - with shocks front and rear and a comfy seat for my aging rump.  It runs well and quietly - no groans, creaks or squeaks, the gears change smoothly and the brakes work properly (not grabbing hard sometimes and acting sloppy other times).   Worth every cent I handed over.

A full suspension is a little overkill for urban riding unless you really ride over a lot of potholes or curbs.  A rear shock adds a fair bit of weight and decreases pedaling efficiency unless you spend a lot of money on a good setup.

As for Kijiji or Craigslist...they can be great ways to find lightly used and inexpensive options, but only if you know what you're looking for and the value of what you find.  I'd add Pinkbike.com to the list, but that's mostly XC racing and freeride bikes.  Most local bike shops will offer free tune ups for a year or longer, which can come in handy as the cables often stretch in the first weeks and months.  After that, basic chain lube will keep these light duty bikes running great for years, unless you ride in the rain and mud a lot.

I remember when I would have laughed at the thought of suspension on a bike.  That was way back in the olden days when I rode a racing bike with skinny tires.  Many years have passed since then and I'm now grateful for the suspension on my wide tired Grannybike!  It means I can still get out and ride despite various health problems.

I used to buy fancy brand name bikes, but they got stolen. Now I ride Canadian Tire bikes, or ones I have rebuilt from scrap.

I don't ride much anymore now - my knees are prosthetic.

This is my around town bike.  My road bike is an 18 wheeler.