First off stop being afraid to look stupid. Walk into a bike shop and start asking questions. Ask anything you like to know and if you don't like the answers go find another bike shop. You might discover that the first guy was telling you something that you weren't ready to accept.
You AREN'T going to get screwed in a local bike shop. The worst you could do is pay a little more for a little more bike than you needed and in the end that bike won't be enough.
If you're financially challenged you can still get information and knowledge from your local bike shop. If that's what you're looking for don't interfere with their other customers or take up their time when they could be working on someone's bike and making a little dough. But most shops are happy to help you learn about the sport.
And then you could head for the Salvation Army or the St Vincent DePaul and you MIGHT find a really nice bike for miraculously cheap.
A guy brought in a Schwinn World into the local shop. It looked much better than new. The chrome was perfect and most of the cheesy components had been replaced with much higher grade equipment. Now the World wasn't the lightest thing around but I wouldn't have though a second time about buying this bike for a hundred and fifty. He got it from the local thrift store for $16.50. The tuneup cost more than the bike did!
He now has it for sale with a $275 tag on it.