I would start with a basic economical bike at first. After ridding a few months you can get a good understanding of what style and type of bike you need. The types and cost of bikes new and used is a wide, wide range. Spend a few hundred on the basics and no matter where you end up you will still have that basic bike to come back to...
Example: 250 USD
https://boston.craigslist.org/bmw/bi...481071571.html