Suggestions for a new bike owner?

[alpinerabbit]

For city riding, definitely no suspension, it will just cut into your budget.

[Biciclista]

Although i'm not suggesting you go get a road bike, I am certain that you COULD get used to the handlebars, if I could do it in my 50's so can you. The trick is to find a bike that actually fits you.

On your budget, all I can suggest is craigslist and garage sales.
and if you have time, go ahead and test ride bikes that might not be what you want. You can learn a lot that way.