Hello! I'm a 5'4", 30 year old woman who weighs 315 and I'd like any and all advice about buying a bike. I've done some research via google, however, I'd like to hear from people who have experienced this! I'm not looking to ride in the Tour de France but would like to go for rides with my boyfriend and have fun exercising. I'm looking for information about the type of bike to look for, what to avoid, how to know if a shop is good with fitting heavy people, etc. I know bikes specifically built for large people can be expensive but I'm hoping to stay under $700 (I don't know what is realistic). Please, share your bike wisdom with me! Thanks.

Edit: I'm in Pennsylvania, in Bucks County which is just outside of Philadelphia.