At a LBS, every transaction is negotiable.

The last two bikes I bought at a LBS (one in Frankfurt, Germany and one in Texas), I selected the gear and fit the bike and said, I'll take it all for XXX which was usually 20% off the total and they we're cool with it.

However, I'm usually a relaxed customer and develop a discussion with the people in the shop and make it clear that I'll be a repeat customer as well.

I assume they see it as an investment. Drop a few lines like, "I check out used bikes on CL but the fit wasn't so well, thus I came here."

Also, a good tune up at a shop for that CL bike will run between 20 and 100 USD.

Go with a new bike, you don't need a rim/tire failure from a 10 year old worn rim/tire. (Especially, if you're new to riding.)