Buy local. Buy often. Shop around and find the best place for you and your hard-earned money. Don't pay any mind to any gun store commandos who talk like they have been a cowboy for 20 years but have never ridden a horse.
When you buy over the internet, you have to pay shipping and transfer fees. Plus you have to consider if the gun is compliant with MD state laws. Internet shopping is good for finding things that are hard to get or locate. But if you buy something from a dude in Iowa and it's not working right or not exactly what you thought, who are you going to take it to?
As far as additional fees, there is a $10 application fee for regulated weapons in MD. Some places charge additional for an integrated lock for pistols, so make sure you check with that before you sign any paperwork and then get hit with more charges when you pick it up.
Welcome to the forums and I'll be seeing you soon when you stop in!
-Andy
Good point. Something I forgot to mention.