Good price for a shooter. Now break it down and clean thoroughly.
http://www.wonderhowto.com/search/luger/
Careful with the left grip. If you lift the base too high you can chip the top around the safety lever. I push it up from the inside, then rotate the base of the grip forward.
Especially clean the inside of the breech block and inside the firing pin. Under the extractor is a place most people miss.
If the barrel is crudded up, clean and brush from the breech. Take it to the range and do like a new rifle barrel. Shoot one, swab, shoot one swab. Go through a magazine then swab and brush. Repeat as necessary. Even well worn luger barrels generally shoot well.
Folks here have found the the Winchester white box, 115 gr. works best. Walmart usually carries it. Lugers like a longer COL. In the 1.160-1.170 range.
FN