What should I consider when shopping for a bicycle?

What you can afford should set the parameters of what you will buy. Go to a bike dealer who can size and fit you to the bike and from there you can peruse the used market for possibly a fancier lighter version. Good bikes last a long time. I have a Schwinn hybrid that didn’t break the bank that is still like the day I bought it 18 years ago and I ride hundreds of miles on it each year.

Don’t do what I did. I bought my bike based on color. Not only is it all wrong for my needs it was pricey. I clearly made a mistake. The puke colored one was ideal for me I just wanted blue.

Frame size is important, let it measure, like @Cruiser wrote.
A laymens way is to, when you sit on the seat, and you hold your foot under the pedal (the pedal that is lowest to the ground) your leg should be almost fully stretched, your knee slightly bend.
A few gears, three or five, could be a good choice for those inclines.
Twenty one is too much, you will not use more than two or three, generally.
Spend a few bucks more, if you can, and buy a good brand (one that gets good critics, maybe you can check the internet for that).
My bicycle was a little bit more expensive than average when my mother bought it.
I use it for ten years now, my mother did so for twenty five!

…fat tire… Duh.

the color… definately color man. Don’t get the purple!

If your have to carry the bike upstairs or downstairs for storage, weight matters.

Fenders are a wonderful thing if you ride in the rain.

For carrying a lot of stuff, a rack in back and Wald grocery baskets are great. Or just zip-tie a milk crate to the rack.

Wald front baskets are pretty great, too.

http://waldsports.com/

How hilly is where you live? That will make a big difference on exactly what “some” gearing will need to be!

As for the hand numbness, have you tried dropped bars? Most people have more problems with drop bars than flat bars when it comes to numbness. Are you going numb on the thumb side or the little finder side? Have you tried padded gloves? I have carpal tunnel syndrom and was showing signs of ulnar nerve problems- special grips, gloves, and a professional fitting and now I have no more problems- and I have a flat-bar bike.

Cruisers are fine for cruising. They aren’t the best for long commutes, or hilly areas, and they aren’t speedy.

The distance of the seat to the handlebars, if too great for your height, can also cause the numbness in your hands and arms and pain in your shoulders. That is another important aspect of fit. I like mountain bikes because I like fatter tires. I feel more secure. I can’t go as fast as on a racing bike but I don’t have blow outs all the time either. And if I feel like riding on the dirt or down a hill I can do it.