In bigger cities, bars will usually only host you if you can provide them with a revenue stream afterwards. This works for social events, such as speed-dating or social Meetups (I've run both types), but not so well for technical meetups UNLESS they get sufficiently large.
Also, companies are usually willing to host Meetups because it's free and easy recruiting that's nearly guaranteed to bring out top talent. This is usually why recruiting agencies are almost always totally willing to give up space for events and sponsor for food and/or drinks; it saves them a ton of time that's usually lost to prospecting.
The first meetup I had was a bit of a vicious cycle - we had no home, which made scheduling hard, which made getting speakers lined up hard.
The second meetup I ran started out a Pivotal Labs which was amazing. Free food, free drink, nice atmosphere, good location - and most importantly, we had "the second Wednesday of every month", which made scheduling ridiculously easy. Actually running the whole meetup was a level of magnitude easier after that. Current venue is also similarly awesome. I wouldn't go back to not having a regularly-scheduled venue.
OH MY GOD, YES.
Hounding people for sponsorships is almost a full time job. It is extremely hard to do this while travelling. In fact, most of the Meetups I've been to, and some that I've hosted, took place at WeWork offices!
In my experiences companies, hackerspaces or coworking places are all quite happy to host tech meetups and it's rarely a problem.